Wetzel, Robert G.
Saunders College Publishing, 1983
Buku Teks
Middleton, Robert Gordon, 1908-
D. B. Taraporevala Sons & Co., 1969
Buku Teks
Farrel, Robert E.
Academic press, 1993
Buku Teks
Ouellette, Robert J.
Macmillan, 1983
Buku Teks
Day, Robert W.
McGraw-Hill, 2012
Buku Teks