Fisher, Robert C.
Dickenson Publishing Company, Inc., 1970
Buku Teks
Juvinall, Robert C.
John Wiley & Sons, c1991
Buku Teks
Cohen, Morris L.
West Publishing Company, 1983
Buku Teks
Weadh, Robert C
Harvard University Press, 1966
Buku Teks
Christopher, Robert C.
Charles E. Tuttle, 1983
Buku Teks