Ulrich, Marie-Helene. Optical spectrum and redshifts of a quasar of extremely high intrinsice luminosity: B2 1225+31. The Astrophysical Journal. 1976, 207: L73–L74. Bibcode:1976ApJ...207L..73U. doi:10.1086/182182.
Colla, G.; Fanti, C.; Ficarra, A.; Formiggini, L.; Gandolfi, E.; Grueff, G.; Lari, C.; Padrielli, L.; Roffi, G.; Tomasi, P; Vigotti, M. A catalogue of 3235 radio sources at 408 MHz. Astronomy & Astrophysics Supplement Series. 1970, 1 (3): 281 [21 October 2017]. Bibcode:1970A&AS....1..281C. (原始内容存档于2019-12-07).
Ulrich, Marie-Helene. Optical spectrum and redshifts of a quasar of extremely high intrinsice luminosity: B2 1225+31. The Astrophysical Journal. 1976, 207: L73–L74. Bibcode:1976ApJ...207L..73U. doi:10.1086/182182.
Iriarte, Braulio; Chavira, Enrique. Blue stars in the North Galactic Cap(PDF). Boletín de los Observatorios de Tonantzintla y Tacubaya. 1957, 2 (16): 3–36 [21 October 2017]. (原始内容存档(PDF)于2017-10-22).
Iriarte, Braulio; Chavira, Enrique. Blue stars in the North Galactic Cap(PDF). Boletín de los Observatorios de Tonantzintla y Tacubaya. 1957, 2 (16): 3–36 [21 October 2017]. (原始内容存档(PDF)于2017-10-22).
Colla, G.; Fanti, C.; Ficarra, A.; Formiggini, L.; Gandolfi, E.; Grueff, G.; Lari, C.; Padrielli, L.; Roffi, G.; Tomasi, P; Vigotti, M. A catalogue of 3235 radio sources at 408 MHz. Astronomy & Astrophysics Supplement Series. 1970, 1 (3): 281 [21 October 2017]. Bibcode:1970A&AS....1..281C. (原始内容存档于2019-12-07).