Gruber, Ruth
Hill and Wang, 1960
Buku Teks
Galbraith, John Kenneth, 1908-2006
Harvard University Press, 1955
Buku Teks
Hanson, Earl Parker
Simon and Shuster, 1955
Buku Teks
Friedrich, Carl J.
Rinehart, 1959
Buku Teks
Sandage, C.H.
Richard D. Irwin, 1961
Buku Teks