Baade, W. and Burbidge, G. R., el al. (1956) Supernovae and Californium 254; Publications of the Astronomical Society of the Pacific; Vol. 68; No. 403; 296-300
Baade, W. and Zwicky, F. (1934) On Super-novae; Proceedings of the National Academy of Sciences of the United States of America; Vol. 20; No. 5; 254-259
Baade, W. and Zwicky, F. (1934) Cosmic Rays from Super-novae; Proceedings of the National Academy of Sciences of the United States of America; Vol. 20; No. 5; 259-263