Abell 28 - C.T. Hua and S. Kwok (1999) (Halpha, [NII], [OIII])
Abell 28 - A. Manchado, M.A. Guerrero, L. Stanghellini, M. Serra-Ricart, 1996, ed. IAC (Halpha+[NII] - [OIII])