N. Nikolov, Catalogue of the Light and Colour Curves of Cepheids in the UBV system, Sofia, 1968

N. Nikolov, G. Ivanov, Normal Color Indices of Cepheids. III, Astronomicheskii Zhurnal, Vol. 47, p. 1004 (1970)

N. Nikolov, G. Ivanov, Normal Color Indices of Cepheids. III, Soviet Astronomy, Vol. 14, p. 806 (1971)

N. Nikolov, G. Ivanov, Intrinsic colours of cepheid variables, Perem. Zvezdy, Byull. (Tom 19) 207-225 (1973)

N. Nikolov, G. Ivanov, On the UV-Excesses of Cepheid Variables, Astronomische Nachrichten, volume 296, p. 207 (1974)

N. Nikolov, G. Ivanov, UV-excesses and the metal abundance of classical cepheids, Astronomicheskii Tsirkulyar, No. 836, p. 2-5 (1974)

N. Nikolov, G. Ivanov, Normal Cepheid color indices. IV, Soviet Astronomy, Vol. 18, p. 77 (1974); Astronomicheskii Zhurnal, Vol. 51, p.132 (1974)

N. Nikolov, G. Ivanov, Standard U-B color indices of Cepheids, Astrofizicheskie Issledovaniia, vol. 1, 1975, p. 25-46. In Russian

N. Nikolov, G.; Ivanov, Intrinsic U-B Colours of Cepheid Variables, Astrophysical Investigations, Vol. 1, p.20 (1975)

N. Iakimova, N. Nikolov, G. Ivanov, On the structure of the Cepheid instability strip, In: Variable stars and stellar evolution; Proceedings of the Symposium, Moscow, USSR, July 29-August 4, 1974. (A76-13026 03-90) Dordrecht, D. Reidel Publishing Co., 1975, p. 201-222.

N. Yakimova, N. Nikolov, G. Ivanov, On the Structure of the Cepheid Instability Strip (review), Variable Stars and Stellar Evolution; Proceedings of the Symposium, Moskovskii Gosudarstvennyi Universitet, Moscow, USSR, July 29-August 4, 1974. Edited by V. E. Sherwood and L. Plaut. Symposium sponsored by the International Astronomical Union Dordrecht, D. Reidel Publishing Co. (IAU Symposium, No. 67), 1975., p.201

N. Nikolov, G. Ivanov, A new list of colour excesses of cepheids, Perem. Zvezdy, Byull. (Tom 20) 63-73 (1975)

G. Ivanov, N. Nikolov, Classical cepheids and the structure of our Galaxy, Stars and galaxies from observational points of view, p. 405-412 (1976)

G. Ivanov, N. Nikolov, On the Pulsation Mode of s-Cepheids, Astrophysical Letters, Vol. 17, p.115 (1976)

G. Ivanov, N. Nikolov, A Discussion of the Cepheid Amplitude Behaviour in the Instability Strip, Astrophysics and Space Science, Volume 60 (2) 329-334 (1979)

N. Nikolov, G. Ivanov, Cepheid instability strip investigation with U-B intrinsic colours, Astronomicheskii Tsirkulyar No.1166, 1981, p.1

N. Nikolov, G. Ivanov, Cepheid Instability Strip Investigation with U-B Intrinsic Colours, Astrophysical Investigations, Vol. 3, p. 1 (1981)

Y. Efremov, G. Ivanov, N. Nikolov, Cepheid Space Distribution and the Structure of the Galaxy, Astrophysics and Space Science, Volume 75 (2) 407-421 (1981)

N. Nikolov, G. Ivanov, On the Problem of Cepheid Amplitude Dependence on the Star Position in the Instability Strip, Compendium in Astronomy, a Volume Dedicated to Professor John Xanthakis on the Occasion of Completing Twenty-Five Years of Scientific Activities as Fellow of the National Academy of Athens. Edited by Elias G. Mariolopoulos, Pericles S. Theocaris, and L.N. Mavridis. Dordrecht: D. Reidel Publishing Company, 1982, p.277, 1982

G. Ivanov, Y. Efremov, N. Nikolov, The Catalogue of Distances and Light Absorption for Cephieds, Peremennye Zvezdy (Volume 21) p. 861 (1983)

G. Ivanov, N. Nikolov, Period / Luminosities Relation of Classical Cepheids, Astrophysics and Space Science, Volume 94, Issue 1, pp. 191-200

V. Golev, G. Ivanov, N. Nikolov, Some applications of signal-to-noise in photographic stellar photometry, Occas. Rep. R. Obs., Edinb. (No. 14) 269-277 (1984)

V. Golev, G. Ivanov, N. Nikolov, Some applications of signal-to-noise in photographic stellar photometry, In Royal Observatory Astron. Phot. 1984 p 269-277 (SEE N85-16102 07-35)

Y. Efremov, G. Ivanov, N. Nikolov, New Stellar Associations in M31, Luminous Stars and Associations in Galaxies, Proceedings of IAU Symposium No. 116, held 26-31 May 1985 in Porto-Kheli, Greece. Edited by C.W.H. De Loore, A.J. Willis, and P. Laskarides. Dordrecht: D. Reidel Publishing Co., p.389, 1986

I. Efremov, G. Ivanov, N. Nikolov, Star Complexes and Associations in the Andromeda Galaxy, Astrophysics and Space Science, Volume 135 (1) 119-130 (1987)

N. Nikolov, S. Xanthakis, Stellar Content of Groupings of Luminous Blue Stars in LMC and M31, The Earth and the Universe, Volume dedicated to Professor Lyssimachos Mavridis on the occasion of his completing forty-five years of academic activities. Edited by G. Asteriadis, A. Bantelas, M.E. Contadakis, K. Katsambalos, A. Papdimitriou, and I.N. Tziavos. Thessaloniki, Greece: Aristotle University of Thessaloniki, 1997, p.227

N. Nikolov, Dmitrij Yakovlevich Martynov (7 April 1904 - 22 October 1989), Astronomical calendar for the year 1991, p. 124 - 126

N. Nikolov, R. Tasheva, UBV Photometry of Bright Stars in the Spiral Arm s5 of M31, Astrophysics and Space Science, Volume 170, Issue 1-2, pp. 257-261 (1990)

N. Nikolov, T. Stefanova, A Project of Astronomy Teaching in the Secondary Schools, The Teaching of astronomy, Proceedings of IAU Colloq. 105, held in Williamstown, MA, 27-30 July 1988. Edited by J.M. Pasachoff and J.R. Percy. Cambridge Univ. Press, 1990., p.284

N. Nikolov, Teaching Human Culture Through Astronomy, The Teaching of astronomy, Proceedings of IAU Colloq. 105, held in Williamstown, MA, 27-30 July 1988. Edited by J.M. Pasachoff and J.R. Percy. Cambridge Univ. Press, 1990., p.47

N. Nikolov, Associations in M31 and M3, 6. Symposium of the Subcommission No. 6 of the Multilateral Cooperation "Physics and evolution of stars": Star clusters and associations, p. 135-146 (1990)

L. Mavridis, N. Nikolov, S. Avgoloupis, P. Varvoglis, The cepheid 1162 Aquilae, Astronomy and Astrophysics, Suppl. Ser., Vol. 80, p. 279-284 (1989)

N. Nikolov, R. Tasheva, Photometry of the Bright Stars Inside and Outside Associations in the Spiral Arm s5 of the Andromeda Galaxy, Astrophysics and Space Science, Volume 152, Issue 2, pp. 239-277 (1989)

I. Efremov, G. Ivanov, N. Nikolov, Star Complexes and Associations in the Andromeda Galaxy, Astrophysics and Space Science, Volume 135, Issue 1, pp. 119-130 (1987)

N. Nikolov, The Venus surface, Priroda (NRB), Tom 36, No. 6, p. 3 - 8 (1987)

N. Nikolov, Astronomy and culture, Fizika, NRB, Tom 12, No. 4, p. 1 - 6 (1987)

N. Nikolov, Study of history of culture by teaching history of astronomy, ESA Spec. Publ., ESA SP-253, p. 329 - 332 (1986)

P. Kunchev, N. Nikolov, A Photometric Study of Three Star Fields in the Southern Region of M33, Astrophysics and Space Science, Volume 127, Issue 2, pp. 327-343 (1986)

N. Nikolov, V. Golev, V. Racheva, Sreshti s kometite Rachev, Sofiia : Nauka i izkustvo, 1986. 1. izd.