Kostyakova, E. B. (2002). Study of spectral variability of the planetary nebula ic 4997 over 25 years (1972-1996). Universidad Nacional Autónoma de México.
Chicago Style (17th ed.) CitationKostyakova, E. B. Study of Spectral Variability of the Planetary Nebula Ic 4997 over 25 Years (1972-1996). Universidad Nacional Autónoma de México, 2002.
MLA (9th ed.) CitationKostyakova, E. B. Study of Spectral Variability of the Planetary Nebula Ic 4997 over 25 Years (1972-1996). Universidad Nacional Autónoma de México, 2002.
Warning: These citations may not always be 100% accurate.