Abell, George O.; Corwin, Harold G., Jr.; Olowin, Ronald P. Svibanj 1989. A catalog of rich clusters of galaxies. Astrophysical Journal Supplement Series. 70 (May 1989): 1–138. Bibcode:1989ApJS...70....1A. doi:10.1086/191333. ISSN0067-0049
Abell, George O.; Corwin, Harold G., Jr.; Olowin, Ronald P. Svibanj 1989. A catalog of rich clusters of galaxies. Astrophysical Journal Supplement Series. 70 (May 1989): 1–138. Bibcode:1989ApJS...70....1A. doi:10.1086/191333. ISSN0067-0049
Abell, George O.; Corwin, Harold G., Jr.; Olowin, Ronald P. Svibanj 1989. A catalog of rich clusters of galaxies. Astrophysical Journal Supplement Series. 70 (May 1989): 1–138. Bibcode:1989ApJS...70....1A. doi:10.1086/191333. ISSN0067-0049