Varol, O. 1982. Calcareous nannofossils from the Antalya Basin, Turkey. N. Jb. Geol. Palaont. Mh., 1982: 244-256
Varol, O. 1983a. Late Cretaceous - Paleocene calcareous nannofossils from the Kokaksu section Zonguldak, Northern Turkey. - N. Jb. Geol. Palaont. Abh., 1663: 431-460
Varol, O. 1983b. Proposed calcareous nannofossil zonation scheme for the Miocene to Holocene of Southeast Asia. - Bul. Geol. Soc. Malaysia, 16: 37-46
Varol, O. 1984. New Neogene calcareous nannofossil taxa from Malta and Southern Turkey. N. Jb. Geol. Palaont. Mh. 1984: 375-384
Varol, O. 1985a. Miocene calcareous nannofossils from the Mut Basin, Southern Turkey. J. Micropalaeont, 42: 127-139
Varol, O. 1985b. The distribution of calcareous nannoplankton in surface sediments from the intertidal and shallow marine regimes of a marginal sea-Jason Bay, South China Sea. - Mar. Micropalaeont. 9: 369-374
Hughes, G. W., Varol, O & Dunkley, P. N. 1986. Pleistocene uplift of Tetepare Island, Solomon Group, as implied by foraminiferal and calcareous nannofossil evidence.-Bul. Roy. Soc. New Zealand 24: 397-408
Varol, O. 1989a. Palaeocene calcareous nannofossil biostratigraphy. In Crux, J.A. & S.E. van Heck (eds.). Nannofossils and their applications. Ellis Horwood, Chichester, 265-310
Varol, O. 1989b. Eocene calcareous nannofossils from Sile, Istanbul Northwest Turkey. Revista Espanola Micropal. 213: 276-320
Varol, O. 1989c. Calcareous nannofossil study of the Central and Western Solomon Islands. Circum Pacific Council for Energy and Mineral Resources, Earth Science Series. 12: 239-268
Varol, O. 1989d. Quantitative analysis of the Arkhangelskiella cymbiformis group biostratigraphic usefulness in the North Sea Area. J. Micropalaeont. 82: 131-134
Varol, O & Jakubowski, M. 1989. Some new calcareous nannofossil taxa. INA Newsletter. 11: 24-29
Al-Rifaiy, I., Varol, O & Lemone, D. 1990. Middle to upper Albian biostratigraphy of the Cuchillo Formation from Sierra de Sapello, Mexico. Newsl. Stratigraphy. 213: 187-200
Varol, O. 1991. New Cretaceous and Tertiary calcareous nannofossils. N.Jb. Geol. Palaeont. Abh. 1821: 211-237
Hughes G. W., Varol, O. & Beydoun, Z. 1991. Evidence for Middle Oligocene rifting of the Gulf of Aden and for Late Oligocene rifting of the southern Red Sea. Marine and Petroleum Geology 8: 354-358
Varol, O. 1992. Revision of the Polycyclolithaceae and its contribution to Cretaceous biostratigraphy. Newsl. Stratigraphy. 273: 93-127
Varol, O.1992. Sullivania, a new genus of Paleogene coccolith. J.Micropaleont. 112: 141-150
Varol, O. & Girgis, M. H. 1994. New taxa and taxonomy of some Jurassic to Cretaceous calcareous nannofossils. N. Jb. Geol. Palaont. Abh. 1922: 221-253.
Klungsoyr, T., Rafdal, J., Einchomb, C. & Varol, O. 1995. The application of an integrated method for the estimation of formation pressure in Vietnam - a case study. -IADC 1995 Asia Pacific Well Control Conference, 1-11.
Varol, O. & Houghton, S. 1996. Didemnid ascidian spicules. J. Micropaleot. 15: 135-149.
Varol, O. 1998. Palaeogene calcareous nannofossil biostratigraphy of the North Sea area. In Bown P. R. (ed.). Chapman & Hall. 200-224.
Varol, O. 2004. Salisia n.g. - a new Pliocene-Pleistocene coccolith genus. N. Jb. Geol. Palaont. Mh. 20042: 119-128
Hughes G. W., Varol O., Gill, E. & Valldeperas T. 2004. Biostratigraphy and depositional environments of Upper Cretaceous carbonates from les Collades de Basturs, southern Central Pyrenees. Cour. Forch.-Ins. Senckenberg, 247: 149-15
Varol, O. 2006. Didemnid ascidian spicules from the Arabian Peninsula. J. Nannofossil Res. 28(1): 35-54
Hughes, G. W., Varol, O. & Al-Khalid, M. 2008. Late Oxfordian micropalaeontology, nannopalaeontology and palaeoenvironments of Saudi Arabia. GeoArabia, 13(2): 15-46
Hughes, G. W., Al-Khalid, M. & Varol, O. 2008. Oxfordian biofacies and palaeoenvironments of Saudi Arabia. GeoArabia, 13(2): 47-60
Varol, O. 2013a. New structural observation within Coccolithus, Clausicoccus, Toweius, Prinsius and Reticulofenestra. Abstract in Geological problem solving with Microfossil III-University of Houston-March10-13, pp.110-112 Abstract
Varol, O. 2013b. Taxonomic revision of Helicosphaera and its contribution to Cenozoic biostratigraphy - Abstract in Geological problem solving with Microfossil III-University of Houston-March10-13, pp.112-114 Abstract
da Gama, R. O. B. P. & Varol, O. 2014a. New Oligocene to Miocene species. J. Nannoplankton Res. 33(1): 1-12
da Gama, R. O. B. P. & Varol, O. 2014b. A new perspective on the structure of Neogene discoasters. J. Nannoplankton Res. 33(1): 23-28
Varol, O. & Bowman, A. R. 2019. Taxonomic revision of selected Late Jurassic (Tithonian) calcareous nannofossils and the application of mobile mounting. N. Jb. Geol. Paläont. Abh. 291/1 (2019): 65-87
Varol, O. 2019. Vonsalisia VAROL nom. nov. pro Salisia VAROL 2004 non LINDLEY 1839. N. Jb. Geol. Paläont. Abh. 291/2 (2019): 229-230
Paez-Reyes. M., Carvajal-Ortiz, H., Sahoo, S. K., Varol, O., Miller, B. V., Hughes, G. W., Gaona-Narvaez, T., Patarroyo, G. D., Curtis, J. H., Lerma, I. & Copeland, P. 20021. Assessing the contribution of the La Luna Sea to the global sink of organic carbon during the Cenomanian-Turonian Oceanic Anoxic Event 2 (OAE2). Global and Planetary Change 199 (2021): 2-23.
Bowman, P. R. & Varol, O., 2021. A Taxonomic Revision of Heliolithaceae - Applications in Resolving the Problematic Calcareous Nannofossil Biostratigraphy of the Paleocene. In M. Montenary, M. (ed.). Calcareous nannofossil biostratigraphy of the Stratigraphy and timescales. 6: 43-223.
Varol, O. 2022. Denisea, a new genus of Paleocene calcareous nannofossils. Neues Jahrbuch für Geologie und Paläontologie, Abhandlungen, 304/2 (2022): 159-186.
Varol, O. & Bowman, A. R. 2022. New Middle Miocene genus OIlladiscoaster. - Abstract in International Nannoplankton Association Meeting , Avignon, France
Varol, O., 2023. New Paleocene Calcareous Nannofossil. Carlamuelleria, Davidbukrya, Mauriceblackia, Noelia and Senelia. Marine Micropaleontology, 180: 1-41
Hughes, G. W. & Varol, O. 2024. Biostratigraphically constrained Neogene palaeoenvironments of the Red Sea rift complex. In Rasul, N. M. A. & Steart. I. C. F. (Eds.). Rifting and Sediments in the Red Sea and Arabian Gulf Regions. 324-341
Varol, O. & Bowman, R. A. 2024. The New Middle Miocene Genus Olladiscoaster, and Related and Associated Discoasters. Grzybowski Foundation Special Publication. 28: 103 pp.
Varol, O. in press. A practical guide to optical studies of calcareous nannofossils. Grzybowski Foundation Special Publication.