Farmer, Richard N., author
Belmont, Cal. Wadsworth 1969,
Buku Teks
Owens, Richard N.
Homewood, Ill. Richard D. Irwin, Inc , 1958
Buku Teks
Farmer, Paul
Clarendon Press, 1994
Buku Teks
Demers, Richard A.
MIT Press, 1991
Buku Teks
Frye, Richard N.
Henry Holt and Company, 1953
Buku Teks