ao afolayan, js mandeep, m abdullah, n s a hamid, t yokoyama.  (2023).  effect of the seed perturbation amplitude on the equatorial spread f initiation during solar minimum.  - advances in space research.  255-267. 

sadia mostafa, mardina abdullah, siti aminah bahari, mohammad tariqul islam.  (2023).  analysis of the regional ionospheric disturbance index during geomagnetic storm in 2012.  - ieee access.  94742-94752. 

ungku azmi iskandar ungku chulan, mardina abdullah, nor fadzillah abdullah, abdullah ramli.  (2023).  machine learning of irreducible error floor in the space-time trellis code.  - international journal of intelligent engineering informatics.  290-312. 

nur fatin irdina zulhamidi, mardina abdullah, nurul shazana abdul hamid, khairul adib yusof, siti aminah bahari.  (2023).  investigating short-term earthquake precursors detection through monitoring of total electron content variation in ionosphere.  - frontiers in astronomy and space sciences.  1-7. 

s.a. bello, m. abdullah, n.s.a. hamid, k.a. yusuf, a. yoshikawa, a. fujimoto.  (2023).  robust least square modelling for selected daytime ionospheric parameters using geomagnetic observations at low latitudes.  - advances in space research.  1615-1633. 

sulaiman ali mohammad, mohd riduan ahmad, mardina abdullah, park sangjong, shamsul ammar shamsul baharin, norbayah yusop, gaopeng lu and vernon cooray.  (2022).  characteristics of lightning electromagnetic fields produced by antarctica storms.  - atmosphere.  1-17. 

khairul adib yusof, mardina abdullah, nurul shazana abdul hamid, suaidi ahadi, essam ghamry.  (2022).  statistical global investigation of pre-earthquake anomalous geomagnetic diurnal variation using superposed epoch analysis.  - ieee transactions on geoscience and remote sensing.  1-13. 

nur izzati mohd rosli, nurul shazana abdul hamid, mardina abdullah, khairul adib yusof, akimasa yoshikawa, teiji uozumi, babatunde rabiu.  (2022).  the variation of counter-electrojet current at the southeast asian sector during different solar activity levels.  - applied sciences.  1-11. 

rasheduzzaman sifat,mohammad rashed iqbal faruque, md bellal hossain, mardina abdullah, mohammad tariqul islam,mayeen uddin khandaker,nissren tamam, abdelmoneim sulieman.  (2022).  development ofdouble c shaped left-handed metamaterial for dual band wifi and satellite communication application with high effective medium radio and wide bandwidth.  - crystals.  1-20. 

n.s.arshad, m.abdullah, s.a.samad, n.abdullah.  (2021).  high-intensity lightning recognition system using very low frequency signal features.  - journal of atmospheric and solar-terrestrial physics.  1-9. 

nouf abd elmunim, mardina abdullah, siti aminah bahari.  (2021).  evaluating the performance of iri-2016 using gps-tec measurements over the equatorial region.  - atmosphere.  1-17. 

khairul adib yusof, mardina abdullah, nurul shazana abdul hamid, suaidi ahadi, essam ghamry.  (2021).  statistical significance of geomagnetic diurnal variation anomalies prior to worldwide earthquake.  - geografia: malaysian journal of society & space.  366-377. 

wan nur izzaty ismail, nurul shazana abdul hamid, mardina abdullah, akimasa yoshikawa, teiji uozumi, zahira mohd radzi.  (2021).  comparison of eej longitudinal variation from satellite and ground measurements over different solar activity levels.  - universe.  1-13. 

khairul adib yusof, mardina abdullah, nurul shazana abdul hamid, suaidi ahadi, akimasa yoshikawa.  (2021).  correlations between earthquake properties and characteristics of possible ulf geomagnetic precursor over multiple earthquakes.  - universe.  1-17. 

saeed abioye bello, nurul shazana abdul hamid, mardina abdullah, akimasa yoshikawa, kornyanat hozumi, takuya tsugawa.  (2021).  equatorial electrojet and electron density over southeast asian region during moderate solar activity condition.  - indian journal of radio and space physics.  125-131. 

idahwati sarudin, nurul shazana abdul hamid, mardina abdullah, suhaila m buhari, kazuo shiokawa, yuichi otsuka, kornyanat hozumi, punyawi jamjareegulgarn.  (2021).  influence of zonal wind velocity variation on equatorial plasma bubble occurrences over southeast asia.  - journal of geophysical research: space physics.  1-10. 

i. sarudin, n. s. a. hamid, m. abdullah, s. m. buhari, k. shiokawa, y. otsuka, c. y. yatini.  (2020).  equatorial plasma bubble zonal drift velocity variations in response to season, local time, and solar activity across southeast asia.  - journal of geophysical research - space physics.  1-12. 

nurliyana abdul rahim, mohd hezri mokhtar, nadirul hasraf mat nayan, muhammad yusof ismail, suhaila m. buhari, mardina abdullah, siti aminah bahari.  (2020).  l-band amplitude scintillations during solar maximum at a low latitude station.  - international journal of advanced trends in computer science and engineering.  465-470. 

roslinda rosli, mardina abdullah, nur choiro siregar, nurul shazana abdul hamid, sabirin abdullah, gan kok beng, lilia halim, noridawaty mat daud, siti aminah bahari, rosadah abd majid, badariah bais.  (2020).  student awareness of space science: rasch model analysis for validity and reliability.  - world journal of education.  170-177. 

a.o. afolayan, j.s. mandeep, m. abdullah, s.m. buhari.  (2020).  observation of the north-south asymmetry in the equatorial spread f intensity at the brazilian longitude.  - advances in space research.  50-63. 

nouf abd elmunim, mardina abdullah, siti aminah bahari.  (2020).  characterization of ionospheric delay and forecasting using gps-tec over equatorial region.  - annals of geophysics.  1-17. 

wan nur arina wan mohd nor, mardina abdullah, mohd riduan ahmad, siti khalijah zainudin, norbayah yusop, wayan suparta, adriana maria gulisano.  (2020).  the response between vtec and lightning activity over the antarctic peninsula.  - polar science.  1-17. 

mohd faisal ibrahim, aqilah baseri huddin, fazida hanim hashim, mardina abdullah, ashrani aizzuddin abd rahni, seri mastura mustaza, aini hussain, mohd hairi mohd zaman.  (2020).  strengthening programming skills among engineering students through experiential learning based robotics project.  - international journal of evaluation and research in education.  939-946. 

a.o. afolayan, j.s. mandeep, m. abdullah, s.m. buhari.  (2019).  statistics of spread f characteristics across different sectors and iri 2016 prediction.  - advances in space research.  2154-2163. 

norbayah yusop, mohd riduan ahmad, mardina abdullah, mona riza mohd esa, sulaiman ali mohammad, wayan suparta, adriana maria gulisano and vernon cooray.  (2019).  seasonal analysis of cloud-to-ground lightning flash activity in the western antarctica.  - atmosphere.  1-16. 

rafidah abd malik, mardina abdullah, sabirin abdullah, yokoyama tatsuhiro & clara y. yatini.  (2019).  development of hf modelling in peninsular malaysia during the rise of solar cycle 24.  - defence s & t technical bulletin.  51-60. 

khairul afifi nasuddin, mardina abdullah, nurul shazana abdul hamid.  (2019).  characterization of the south atlantic anomaly.  - nonlinear processes in geophysics.  25-35. 

norbayah yusop, mohd riduan ahmad, mardina abdullah, siti khalijah zainudin, wan nur arina wan mohd nor, kemal maulana alhasa, mona riza mohd esa, muhammad haziq mohamad sabri, wayan suparta, adriana maria gulisano, vernon cooray.  (2019).  cloud-to-ground lightning observations over the western antarctic region.  - polar science.  84-91. 

khairul adib yusof, nurul shazana abdul hamid, mardina abdullah, suaidi ahadi, akimasa yoshikawa.  (2019).  assessment of signal processing methods for geomagnetic precursor of the 2012 m6.9 visayas, philippines earthquake.  - acta geophysica.  1297-1306. 

wan nur izzaty ismail, nurul shazana abdul hamid, mardina abdullah, nurul hafizah mohd shukur, akimasa yoshikawa.  (2019).  variation of equatorial electrojet current profiles over solar phases.  - asm science journal.  125-133. 

s. a. bello, m. abdullah, n. s. a. hamid, b. w. reinisch, a. yoshikawa, a. fujimoto.  (2019).  response of ionospheric profile parameters to equatorial electrojet over peruvian station.  - earth and space science.  617-628. 

abimbola o. afolayan, mandeep jit singh, mardina abdullah, suhaila m. buhari, tatsuhiro yokoyama, pornchai supnithi.  (2019).  observation of seasonal asymmetry in the range spread f occurrence at different longitudes during low and moderate solar activity.  - annales geophysicae.  733-745. 

zainuddin mz, abdullah m, abidin zz, bahari sa, asillam mf, hashim mh, radzi z.  (2019).  review on space science research in malaysia.  - asm science journal.  107-124. 

n.s. arshad, m. abdullah, s.a. samad & n.m. hatta.  (2019).  lightning severity classification technique using very low frequency signal feature extraction.  - journal of atmospheric and solar-terrestrial physics.  1-10. 

s. bohanudin, m. ismail, m. abdullah, and f. adlan.  (2018).  minimizing mobile location error based on hybrid toa-cta for heterogeneous network.  - journal of telecommunication, electronic and computer engineering.  . 

m. abdullah, r.a. majid, b. bais, n.s. bahri, m.f. asillam.  (2018).  fostering research aptitude among high school students through space weather competition.  - advances in space research.  478-486. 

rosadah abd majid, mardina abdullah, badariah bais, nor syaidah bahri, mohd hezri mokhtar, siti aminah bahari.  (2018).  relationship between students' attitudes in space science with their achievements in the field.  - creative education.  . 

alfonsi, l., povero, g., luca, s., cesaroni, c., forte, b., mitchell, c. n., burston, r., veettil, s. v., aquino, m., klausner, v., muella, m. t. a. h., pezzopane m., giuntini a., hunstad, i., franceschi, g. d., musico, e., pini, m. & nine others.  (2018).  analysis of the regional ionosphere at low latitudes in support of the biomass esa mission.  - ieee transactions on geoscience and remote sensing.  . 

mohamad fakhari mehrjardi, hilmi sanusi, mohd. alauddin mohd. ali, mardina abdullah.  (2018).  integrated attitude-orbit dynamics and control of spacecraft systems: state of the art and future trends.  - ieee aerospace & electronic systems magazine.  . 

rohaida mat akir, mardina abdullah, kalaivani chellapan, alina marie hasbi and siti aminah bahari.  (2017).  comparative study of tec for gistm stations in the peninsular malaysia region for the period of january 2011 to december 2012.  - advanced science letters.  1304-1309. 

ahmad ridzuan mohammed shariff, norhazlina harun, mandeep singh jit singh, kalaivani chellappan, wayan suparta, fredolin t. tangang, maszidah muhammad, mardina abdullah, and mohammad tariqul islam.  (2017).  utilization of wind steadiness index for identification of malaysian northeast monsoon onset and withdrawal from 2011 to 2015.  - advanced science letters.  1440-1443. 

nouf abd elmunim, mardina abdullah, alina hasbi, and siti aminah bahari.  (2017).  investigation on the implementation of the holt-winter method for ionospheric delay forecasting.  - advanced science letters.  1325-1328. 

n.a. elmunim, m. abdullah, a.m. hasbi, s.a. bahari.  (2017).  comparison of gps tec variations with holt-winter method and iri-2012 over langkawi, malaysia.  - advances in space research.  276-285. 

suhaila m buhari, mardina abdullah, yuichi otsuka, tatsuhiro yokoyama, michi nishioka, alina marie hasbie and takuya tsugawa.  (2017).  pengesanan gelembung plasma di dalam lapisan ionosfera menggunakan penerima gps di asia tenggara.  - sains malaysiana.  879-885. 

tam dao, yuichi otsuka, kazuo shiokawa, michi nishioka, mamoru yamamoto, suhaila m. buhari, mardina abdullah and asnawi husin.  (2017).  coordinated observations of postmidnight irregularities and thermospheric neutral winds and temperatures at low latitudes.  - journal of geophysical research: space physics.  7504-7518. 

mohammed saeed mohammed, mandeep jit singh, mardina abdullah.  (2017).  new transmitted reference receiver technique to lessen the mui at wpan.  - sylwan.  1-9. 

ungku azmi ungku chulan, mardina abdullah, nor fadzilah abdullah.  (2017).  towards the prediction of irreducible error floor in space time trellis code.  - ieee communications letters.  . 

mohammed saeed mohammed, mandeep jit singh, mardina abdullah.  (2017).  new tr-uwb receiver algorithm design to mitigate mui in concurrent schemes.  - wireless personal communications.  4431-4450. 

siti aminah bahari, mardina abdullah, baharudin yatim.  (2017).  variasi jumlah kandungan elektron ionosfera di malaysia ketika solar minimum.  - sains malaysiana.  1987-1995. 

malik, r. a, abdullah, m, abdullah, s, homam, m. j, yokoyama, t, yatini, c. y.  (2017).  prediction and measurement of high frequency radio frequencies in peninsular malaysia and comparisons with the international reference ionosphere model.  - advanced science letters.  1294-1298. 

tv omotosho, sa akinwumi, oo ometan, mo adewusi, js mandeep, m abdullah.  (2017).  earth-space rain attenuation prediction: its impact at ku, ka and v-band over some equatorial stations.  - journal of informatics and mathematical sciences.  359-374. 

s.a. bello, m. abdullah, n.s.a. hamid, a. yoshikawae, a.o. olawepo.  (2017).  variations of b0 and b1 with the solar quiet sq- current system and comparison with iri-2012 model at ilorin.  - advances in space research.  307-316. 

saeed abioye bello ,mardina abdullah , nurul shazana abdul hamid.  (2017).  investigation of ionospheric minimum frequency near dip equator.  - advanced science letters.  1329-1332. 

s.m buhari, m. abdullah, t. yokoyama, y.otsuka, m. nishioka, a.m hasbi, s.a bahari and t.tsugawa.  (2017).  climatology of successive equatorial plasma bubbles observed by gps roti over malaysia climatology.  - journal of geophysical research: space physics.  1-11. 

norbaizura yaso, alina marie hasbi & mardina abdullah.  (2016).  investigation of ionospheric and geomagnetic response during 2011 tohoku earthquake using ground based measurement.  - indian journal of radio & space physics.  115-125. 

siti nurbaiti ibrahim, mohamad huzaimy jusoh, ahmad asari sulaiman, siti noor aisyah ahmad, mohd zul hilmey makmud, baba musta, mardina abdullah, mhd fairos asillam, nyanasegari bhoo pathy, mohd helmy hashim, yoshikawa akimasa.  (2016).  first geomagnetic observation at sabah, malaysia by using magdas array.  - international journal of simulation: systems, science & technology.  1-8. 

s.a. bahari, m. abdullah, a.m. hasbi, b. yatim, w. suparta, a. kadokura, g. bjornsson.  (2016).  study of high-latitude ionosphere: one-year campaign over husafell, iceland.  - journal of atmospheric and solar-terrestrial physics.  45-52. 

r.a. malik,m. abdullah, s. abdullah, m.j. homam.  (2016).  comparison of maximum usable frequency (muf) variability over peninsular malaysia with iri model during the rise of solar cycle 24.  - journal of atmospheric and solar-terrestrial physics.  87-92. 

wayan suparta, maszidah muhammad, mandeep singh jit singh, fredolin t. tangang, mardina abdullah, mohammad tariqul islam.  (2016).  variability of gps water vapor associated with warming activity in peninsular malaysia during the period of 2008 - 2011.  - journal of water and climate change.  240-250. 

bohanudin s., ismail m., abdulah m..  (2015).  the accuracy of time-based hybrid localization technique in heterogenous wireless network.  - journal of theoretical and applied information technology.  35-42. 

n a elmunim1, m abdullah, a m hasbi1, s a bahari.  (2015).  comparison of statistical holt-winter models for forecasting the ionospheric delay using gps observations.  - indian journal of radio & space physics.  28-34. 

teh w.-l., abdullah m., hasbi a.m..  (2015).  lack of relationship between geoeffectiveness and orientations of magnetic clouds with bipolar b z and unipolar southward b z.  - planetary and space science.  27-34. 

shariff, ahmad ridzuan mohammed; singh, mandeep singh jit; chellappan, kalaivani; suparta, wayan; tangang, fredolin t.; salimun, ester; muhammad, maszidah; abdullah, mardina; islam, mohammad tariqul.  (2015).  a preliminary study of cold surges and precipitation during the northeast monsoon season over malaysia.  - advanced science letters.  185-188. 

siti sarah nik zulkifli, rosdiadee nordin, mahamod ismail, mardina abdullah.  (2015).  investigation of bandwidth allocation based on rat selection in a wireless heterogeneous network for smart home application.  - journal of theoretical and applied information technology.  94-100. 

b. bais, m. abdullah, a. mohamed.  (2015).  development of online project registration and management system (eprm) for masters by coursework.  - journal of engineering science and technology.  18-27. 

aramesh seif, roland t. tsunoda, mardina abdullah, alina marie hasbi.  (2015).  daytime gigahertz scintillations near magnetic equator: relationship to blanketing sporadic e and gradient-drift instability.  - earth, planets and space.  1-13. 

tv omotosho, js mandeep, m abdullah.  (2014).  cloud cover cloud liquid water and cloud attenuation at ka and v bands over equatorial climate.  - meteorological applications.  21:777-785. 

ahmad s.n.a., jusoh m.h., shariff k.k.m., abdullah m., asillam m.f., veenadhari b., uozumi t., abe s., yoshikawa a., cardinal m.g..  (2014).  data processing method to classify pc5 ulf pulsations due to solar wind perturbations at equatorial region.  - wseas transactions on signal processing.  337 - 344. 

tv omotosho, ml akinyemi, js mandeep, m abdullah.  (2014).  total atmospheric absorption of fixed satellite communication signal due to oxygen and water vapor in nigeria.  - ieee antennas and propagation magazine.  56(2):108-121. 

ibrahim y. sokar, md. yusoff jamaluddin, mardina abdullah.  (2014).  short-term performance prediction model for aviation job-shop.  - journal of applied sciences, engineering and technology.  7(7):1256-1261. 

wai leong, teh; mardina, abdullah; alina, hasbi.  (2014).  evidence for the core field polarity of magnetic flux ropes against the reconnection guide field.  - journal of geophysical research: space physics.  1-5. 

s. m. buhari, m. abdullah, a.m. hasbi, y. otsuka, t. yokoyama, m. nishioka, and t. tsugawa.  (2014).  continuous generation and two-dimensional structure of equatorial plasma bubbles observed by high-density gps receivers in southeast asia.  - journal of geophysical research:space physics.  10,569-10,580. 

intan izafina idrus, mardina abdullah, alina marie hasbi, asnawi husin, baharuddin yatim.  (2013).  large-scale traveling ionospheric disturbances observed using gps receivers over high-latitude and equatorial regions.  - journal of atmospheric and solar-terrestrial physics.  102:321-328. 

tv omotosho, js mandeep, m abdullah, at adediji.  (2013).  distribution of one-minute rain rate in malaysia derived from trmm satellite data.  - annales geophysicae.  31(11):2013-2022. 

temidayo victor omotosho, jit singh mandeep, mardina abdullah.  (2013).  cloud attenuation studies of the six major climatic zones of africa for ka and v satellite system design.  - annals of geophysics.  56(5):1-18. 

wayan suparta, faizatul noor abu bakar, mardina abdullah.  (2013).  remote sensing of antarctic ozone depletion using gps meteorology.  - international journal of remote sensing.  34(7):2519-2530. 

salut, m.m. , abdullah, m, graf, k.l, cohen, m.b, cotts, b.r.t., kumar.s,.  (2012).  long recovery vlf perturbations associated with lightning discharges.  - journal of geophysical research a: space physics.  117(8):Art.no A08311. 

wayan suparta, faizatul noor abu bakar and mardina abdullah.  (2012).  coreless winter characteristics observed with global positioning system receivers over antarctic and arctic regions.  - american journal of applied sciences.  9(8):1203-1213. 

mustafa dh. hassib, js mandeep, mardina abdullah, mahamod ismail, rosdiadee nordin and mt islam.  (2012).  improved concatenated (rs-cc) for ofdm systems.  - ieice electronics express.  9(6):538-543. 

aramesh seif, mardina abdullah, alina marie hasbi, yuhua zou.  (2012).  investigation of ionospheric scintillation at ukm station, malaysia during low solar activity.  - acta astronautica.  81:92-101. 

j.s. mandeep, anthony cheng chen yee, m. abdullah, m tariqul.  (2011).  comparison and analysis of tropospheric scintillation models for northern malaysia.  - acta astronautica.  69(1-2):2-5. 

asnawi husin, m. abdullah, m. a. momani.  (2011).  observation of medium-scale traveling ionospheric disturbances over peninsular malaysia based on ipp trajectories.  - radio science.  46(2):RS2018. 

temidayo victor omotosho, jilt singh mandeep and mardina abdullah.  (2011).  cloud-cover statistics and cloud attenuation at ka-and v-bands for satellite systems design in tropical wet climate.  - ieee antenna and wireless propagation letters.  10:1194-1196. 

siti sarah nik zulkifli, mardina abdullah, mahamod ismail.  (2011).  simulation of ionospheric error on gps signals due to changes in the direction of mobile station positions in differential gps.  - annals of geophysics.  54(6):756-760. 

ibrahim y sokar, md yusoff jamaluddin, mardina abdullah, zayed alarabi khalifa.  (2011).  kpis target adjustment based on trade-off evaluation using fuzzy cognitive maps.  - australian journal of basic and applied sciences.  5(12):2048-2053. 

siti aminah bahari, mardina abdullah and baharudin yatim.  (2011).  the response of tec at quasi-conjugate point gps stations during solar flares.  - acta geophysica.  59(2): 407-427. 

jit singh mandeep, anthony cheng chen yee, mardina abdullah and mohammad tariqul islam.  (2011).  tropospheric scintillation measurements in ku-band satellite signals on earth-space paths with low elevation angle.  - idojaras.  115(4):265-273. 

abushagur, aag; abbou, fm; abdullah, m; misran, n.  (2011).  performance analysis of a free-space terrestrial optical system in the presence of absorption, scattering, and pointing error.  - optical engineering.  50(7):075007. 

m. abdullah, j.s. mandeep, s. zainuddin, s. abdullah and a.f.m. zain.  (2011).  variation of fof2 prior to earthquakes.  - journal of metrology society of india.  26(2):97-103. 

m. abdullah, h.j. strangeways, s.s.n. zulkifli.  (2010).  ionospheric differential error determination using ray tracing for a short baseline.  - advances in space research.  46:1326-1333. 

j. s. mandeep & y. y. ng & h. abdullah & m. abdullah.  (2010).  the study of rain specific attenuation for the prediction of satellite propagation in malaysia.  - journal of infrared, millimeter, and terahertz waves.  31(6):681-689. 

m. abdullah, a.f.m. zain, m.h. jusoh, n. misran and w.a. mubarak.  (2009).  ionospheric total electron content response to the december 26, 2004 north sumatra earthquake.  - american journal of applied sciences.  6(4):685-690. 

norsuzila ya`acob, mardina abdullah, mahamod ismail dan azami zaharim.  (2009).  model validation for gps total electron content using 10th polynomial function technique at an equatorial region.  - wseas transactons on computers.  8(9):1533-1542. 

abdullah s., rahmat r.a.a.o.k., zaharim a., muhamad n., deros b.m., kofli n.t., abdullah m., mohd. tahir m., muchtar a., azhari c.h..  (2009).  implementing continual review of programme educational objectives and outcomes for obe curriculum based on stakeholders` input.  - european journal of scientific research.  29(1):89-99. 

ya`acob n., abdullah m., ismail m., zaharim a..  (2009).  model validation for total electron content (tec) at an equatorial region.  - european journal of scientific research.  28(4):643-649. 

mardina abdullah, hal j. strangeways, david m. a. walsh.  (2009).  improving ambiguity resolution rate with an accurate ionospheric differential correction.  - journal of navigation.  62(1):151-166. 

ya`acob n., abdullah m., mahamod i., zaharim a..  (2009).  model validation for gps total electron content (tec) using 10th polynomial function technique at an equatorial region.  - wseas transactions on computers.  8(9):1533-1542. 

ya`acob n., abdullah m., ismail m., zaharim a..  (2009).  improving ambiguity resolution using an ionospheric differential correction.  - european journal of scientific research.  29(1):6-12. 

zulkifli s.s., abdullah m., zaharim a., ismail m..  (2009).  ionospheric effects on gps range finding using 3d ray-tracing and nelder-mead optimisation algorithm.  - wseas transactions on mathematics.  8(1):1-10. 

mohammad awad momani, mohd alauddin mohd ali, baharudin yatim, mardina abdullah and norbahia misran.  (2008).  gps observations at quasi-conjugate points under disturbed conditions.  - acta geophysica.  56(4):1179-1201. 

zain, a.f.m., s. abdullah, m.j. homam, f.c. seman, m. abdullah, and y.h. ho.  (2008).  observations of the f3-layer at equatorial region during 2005. ..  - journal of atmospheric and solar-terrestrial physics.  70(6):918-925. 

mardina abdullah, hal j. strangeways and david m.a. walsh.  (2007).  effects of ionospheric horizontal gradients on differential gps.  - acta geophysica.  55(4):509-523.