Sandage, C.H.
Richard D. Irwin, 1960
Buku Teks
Shelly Rodgers and Esther Thorson
Routledge, 2012
Buku Teks
Wells, William D.
Prentice-Hall, 2000
Buku Teks
Wells, William D.
Prentice-Hall, 2000
Buku Teks
Moriarty, Sandra E. (Sandra Ernst)
Pearson, 2012
Buku Teks