Georges Paturel; Dubois P.; Petit C.; Woelfel F. (), Comparison LEDA/SIMBAD octobre 2002. Catalogue to be published in 2003 (în engleză), Bibcode:2002LEDA.........0P, WikidataQ66470150
Claus Leitherer; Ronald Allen; Artashes Petrosian; Brian McLean; Daniel Kunth (martie 2008). „The North Galactic Pole +30° Zone Galaxies. I. A Comparative Study of Galaxies with Different Nuclear Activity”. The Astrophysical Journal Supplement Series (în engleză). 175 (1): 86–96. Bibcode:2008ApJS..175...86P. doi:10.1086/523105. WikidataQ57630397.
Claus Leitherer; Ronald Allen; Artashes Petrosian; Brian McLean; Daniel Kunth (martie 2008). „The North Galactic Pole +30° Zone Galaxies. I. A Comparative Study of Galaxies with Different Nuclear Activity”. The Astrophysical Journal Supplement Series (în engleză). 175 (1): 86–96. Bibcode:2008ApJS..175...86P. doi:10.1086/523105. WikidataQ57630397.
Georges Paturel; Dubois P.; Petit C.; Woelfel F. (), Comparison LEDA/SIMBAD octobre 2002. Catalogue to be published in 2003 (în engleză), Bibcode:2002LEDA.........0P, WikidataQ66470150
Claus Leitherer; Ronald Allen; Artashes Petrosian; Brian McLean; Daniel Kunth (martie 2008). „The North Galactic Pole +30° Zone Galaxies. I. A Comparative Study of Galaxies with Different Nuclear Activity”. The Astrophysical Journal Supplement Series (în engleză). 175 (1): 86–96. Bibcode:2008ApJS..175...86P. doi:10.1086/523105. WikidataQ57630397.