Drozdovsky, I. O.؛ Karachentsev, I. D. (2000). "Photometric distances to six bright resolved galaxies". Astronomy and Astrophysics Supplement. ج. 142 ع. 3: 425–432. Bibcode:2000A&AS..142..425D. DOI:10.1051/aas:2000155.
R. M. Gonzalez Delgado؛ E. Perez؛ C. Tadhunter؛ J. M. Vilchez؛ J. M. Rodriguez-Espinosa (2000). "H II Region Population in a Sample of Nearby Galaxies with Nuclear Activity. I. Data and General Results". Astrophysical Journal Supplement. ج. 108 ع. 1: 155. Bibcode:1997ApJS..108..155G. DOI:10.1086/312951.
Drozdovsky, I. O.؛ Karachentsev, I. D. (2000). "Photometric distances to six bright resolved galaxies". Astronomy and Astrophysics Supplement. ج. 142 ع. 3: 425–432. Bibcode:2000A&AS..142..425D. DOI:10.1051/aas:2000155.
R. M. Gonzalez Delgado؛ E. Perez؛ C. Tadhunter؛ J. M. Vilchez؛ J. M. Rodriguez-Espinosa (2000). "H II Region Population in a Sample of Nearby Galaxies with Nuclear Activity. I. Data and General Results". Astrophysical Journal Supplement. ج. 108 ع. 1: 155. Bibcode:1997ApJS..108..155G. DOI:10.1086/312951.