Gross, Harver, author
University of Michigan Press, 1964
Buku Teks
Hobsbaum, Philip
Routledge, 1996
Buku Teks
Hubell, Jay Broadus, author
Macmillan, 1922
Buku Teks
Arp, Thomas R., author
Macmillan, 1966
Buku Teks
Prost, Louise 1907-
The University of Iowa City, 1933
Buku Teks