B. Kowatschew, Y Cassuioeuae un Jahre 1973, Astronomischen Gesellschaft und der Arbeitsgemeinschaft Extra Terrestrische Physik, v. 6m bit 9, Marz 1974, s. 307; s. 319

B. Kowatschew, Y Cassiopeiae in 1973, Bulletin of the American Astronomical Society, v. 5, Nr 4, Part 1, 1973, p. 379; p. 413

Sietter, Buerbeck, B. Kowatschew, Y Cassiopeiae im Jahre 1973; B. Kowatschew, Anderung der Aquivalentbreiten mit der Phase bei dem Bedechungsveranderlichen 68 u Herculis, Rahmenprogramm, 6-8 March 1974, Munchen

W. Seitter, H. Durbeeck, B. Kowatschew, Gamma Cassiopeiae im Jahre 1973, Mitteilungen, Nr. 35. 6-9 March 1974, Hamburg, p. 188

B. Kowatschew, Gasstrom im System 68u Herculis, Mitteilungen, Nr. 35. 6-9 March 1974, Hamburg, p. 188

B. Kovachev, W. Seggewiss, A new spectroscopic orbit of the eclipsing binary 68U Her, Astron. Astrophys. Suppl. v. 19, s. 395-402

B. Kovachev, M. Reinhardt, Spectroscopic Evidence for Extrastellar Matter in u Her, ACTA Astronomica, v. 25, No 2, 1975, p. 133-151

B. Kovachev, H. W. Duerbecj, A Coarse Analysis of the B1 Ia Star kapa Cas, ACTA Atronomica, v. 26, No 4, 1976, p. 305-317

V. Mineva, B. Kovachev, T. Radoslavova, Spectrophotometric exploration of the alpha Col Star, Доклады БАН, т. 34, кн. 12, 1981, с. 1625-1628

V. Mineva, G. Petrov, B. Kovachev, Spectrophotometric Study of Galaxies with high surface brightness I Arakelian 144, Доклады БАН, т. 34, кн. 12, 1981, с. 1629-1632

V. Mineva, B. Kovachev, L. Luud, Spectrophotometry of 55 CYG, Доклады БАН, т. 35, кн. 6, 1982, с. 721-724

G. Petrov, B. Kovachev, V. Mineva, Physical conditions in the Galaxy nuclei with emission lines, Markarian 558, Доклады БАН, т. 35, кн. 6, 1982, с. 725-728

L. Iliev, B. Kovachev, N. Tomov, UBV Observations of EW Lac during 1982 and 1983, Buletin d'information su les etoiles Be Be star Newsletter, Nr 10, September 1984, p. 11-28

V. Shkodrov, B. Kovachev, On radial velocity and the motion of spectroscopy binary stellar systems, Доклады БАН, т. 36, кн. 1, 1983, с. 11-13

B. Kovachev, M. Tsvetkov, V. Tsintsarov, Processing of Photographic Observing Material at the National Astronomical Observatiry Rozhen, Astronomical Photography, 1984, Proceedings edited by M. Elizabeth Sim, Keiichi Ishida, p. 165-172

V. Mineva, G. Petrov, B. Kovachev, Physical conditions in Nucleus of seyfert galaxy NGC 7469, Доклади на БАН, т. 36, кн. 6, 1983, с. 713-716

G. Petrov, V. Mineva, B. Kovachev, G. Kyazoumov, Rotation, Mass and physical conditions in nucleus of spiral galaxy NGC 7537, Доклади на БАН, т. 36, кн. 6, 1983, с. 717-719

L. Iliev, B. Kovachev, N. Tomov, Three-colour UBV photometry of Be-Shell star EW LAC, Доклады БАН, т. 37, кн. 8, 1984, с. 983-985

D. Dimitrov, B. Shkodrov, B. Kovachev, External Heating on doppler profiles of spectral lines, Доклади на БАН, т. 38, кн. 7, 1985, с. 811-813

G. Petrov, G. Kayazumov, B. Kovachev, V. Mineva, Dynamics, mass and physical characteristics of the spiral galaxies NGC 1084, 6503, 7339 and 7537, БАН, Астрофизичекие исследования, т. 5, 1989, с. 3-12

G. Petrov, B. Kovachev, V. Mineva, Some spectrophotometric data for 31 Galaxies from karchentsev's list, Astrophysics and Space Science, v. 116, 1985, p. 333-340

K. Panov, B. Kovachev, M. Ivanova, CH CYGNI in the transition to its cool phase, Astrophysics and space science, v. 116, No 2, 1985, 355-365

B. Kovachev, Nationalobservatorium der Bulgarischen Akademie der Wissenschaften, Mitteilungen der Astronomischen Gesellschaft No 65, Kosmische Plasmen Kleine Korper im Sonnensystem, Gottingen, 7-11 April 1986, s. 178-179

L. Hric, D. Chochol, B. Kovachev, Spectroscopic variations of the symbiotic nova PU VUL, The Symbiotic phenomenon, Proceedings of the 103 RD Colloquium of the International Astronomical Union, Torun, Poland, 18-20 August 1987, p. 283-284

V. Mineva, B. Kovachev, Rotational moments o galaxies - members of multiple systems of different types, Астрофизически изследвания, БАН, кн. 6, 1991, с. 32-38

V. Tzintzarov, Ts. Georgiev, M. Tsvetkov, B. Kovachev, M. Panov, Hypersensitization of Kodak IN Emulsions at the Rozhen National Astronomical Observatory, Astrophotography, Proceedings of the IAU Workshop, Editor S. Marx, Jena, 21-24 April 1987, s. 42-46

L. Iliev, B. Kovachev, Commission 27 of the I. A. U. Information Bulletin on variable stars, Nos 3201-3300, June 1988 - March 1989, Editors L. Szabados, B. Szeidl, Konkoly observatory, H - 1525 Budapest, P.O. Box 67, Hungary, p. 1-3

C. Stagg, H. Bozic, A. Fullerton, W. Gao, Z. Guo, P. Harmanec, J. Horn, L. Huang, L. Iliev, P. Koubsky, B. Kovachev, K. Pavlovski, J. Percy, F. Schmidt, S. Stefl, N. Tomov, J. Ziznovsky, A photometric campaign on the Be stars o and, KX And, KY And, LQ And amd EWLac, Monthly notices of the Royal Astronomical Society, containing papers published in the period 1988 September to October, v. 234, p. 1021-1049

M. Tsvetkov, B. Kovachev, Flare stars investigations at the department of Astronomy and the Rozhen National Astronomical Observatory, Sollar and Stellar Flares, I.A.U. Colloquium No 104, Poster Papers, 15-19 August 1988, Stanford Universiity, California, USA, 1989, p. 151-154

B. Kovachev, N. Tomov, M. Tomova, Three-colour photoelectric photometry of the symbiotic star AG PEG, Доклады БАН, т. 42, кн. 6, 1989, с. 5-6

J. Borisova, B. Kowatschev, Spectral investigation of Be stars landa ER1 and kapa OPH FOR NRP phenomenon, Evolution of Stars, IAU Symp. No 145, Abstract of Presented Papers, Варна, 27-31 август 1990, p. 36

L. Iliev, B. Kovachev, Changes in the pleione's shell - transition to a dissipation phase, Symposium 145, 27-31 August 1990, p. 40

E. Mechenkova, B. Kovachev, Structure and spectral peculiarities of the circumstellar matter in the system V 367 CYGHI, IAU, Symposium 145, 27-31 August 1990, p. 45

L. Iliev, B. Kovachev, Changes in the spectrum of pleione: Phase of shell dissipation, Evolution of Stars: the photospheric abundance connection, Poster Papers presented at the 145 symposium of the International Astronomical Union, Zlatni Pjasaci, Bulgaria, 27-31 August 1990, p. 127-128

L. Iliev, B. Kovachev, N. Tomov, 59 Cygni - photometric behaviour after the active period, Астрофизически изследвания БАН, 6, 1991, с. 47-54

E. Mechenkova, B. Kovachev, Structure and spectral pecularities of the circumstelar matter in the system V 367 CYGNI, Evolution of Stars: the photospheric abundance connection, Poster Papers presented at the 145 symposium of the International Astronomical Union, Zlatni Pjasaci, Bulgaria, 27-31 August 1990, p. 133-134

I. Borisova, E. Chelebiev, B. Kowatschev, Spectral Investigation of some Be stars for NRP phenomenon, ESD Workshop of rapid variability of OB Stars Nature and Diagnostig Value, 1991, p. 49-50

G. Petrov, B. Kovatchev, Searching for Galaxies in voids - first results, Доклади на БАН, т. 45, кн. 6, 1992, с. 5-8

B. Kovachev, G. Petrov, Searching for galaxies in voids, Доклади на БАН, т. 45, кн. 9, 1992, с. 9-10

G. Petrov, B. Kovachev, A. Strigatchev, A search for galaxies in voids - first results, Abstract Series 9, Bochum, 27 September - 1 October 1993, p. 48

B. Kovachev, New details of the Classical Classification - Scheme of Galaxies, Доклади на БАН, т. 48, кн. 4, 1995, с. 5-8

B. Kovachev, Photometric Study of a Spiral Galaxy, Доклади на БАН, т. 48, кн. 3, 1995, с. 5-9

G. Petrov, A. Strigatchev, B. Kovachev, Studying of the void 2320+1339, Доклади на БАН, т. 47, кн. 6, 1994, с. 9-12

U. Hopp, B. Kuhn, U. Thiele, K. Birkle, H. Elsasser, B. Kovachev, A redshift survey for faint galaxies towards voids of galaxies, Astronomy and astrophysics, Supplement series, March 1995, p. 537-549

B. Kovachev, G. Petrov, A. Strigachev, V. Mineva, Preliminary photometric and morphological investigations of Galaxies in Pisces Cetus Void, Доклади на БАН, т. 48, кн. 2, 1995, с. 5-8

J. Vennik, U. Hopp, B. Kovachev, B. Kuhn, H. Elsasser, Surface photometry of galaxies in low density regions, Astronomy and astrophysics, Supplement series, 1 June 1996, p. 261-280

G. Petrov, B. Kovachev, Photometry and Morphology of Faint Galaxies in the Direction of the Void 0049+05, Доклади на БАН, 1997, т. 50, кн. 11-12, с. 5-8

V. Kuhn, B. Kovachev, Слаби галактики в близки Voids, Доклади на БАН, т. 51

B. Kovachev, On the problem of gaseous envelopes in early type supergiants, Доклади на БАН, т. 50, кн. 11-12, 1997, с. 9-12

G. Petrov, W. Seggewiss, A. Dieball, B. Kovachev, CCD standards for U and I in the open cluster NGC 7790 Astronomy and astrophysics, 2001, т. 376, p. 745-750