Wesson, Robert G., author
Houghton Miffiln, 1977
Buku Teks
edited by Robert W. Tucker, Charles B. Keely and Linda Wrigley
Westview Press, 1992
Buku Teks
Langdon, Robert M., author
Littlefield Adams, 1961
Buku Teks
edited by Robert A. Scalapino
University of California Press, 1977
Buku Teks
Kajima, Morinosuke, author
Charles E. Tuttle, 1969
Buku Teks