Lightstone, A. H.
Harper & Row, 1965
Buku Teks
Research and Education Association, 1987
Buku Teks
Wahidin
Jakarta: Nabila Teknik Group, 1975
Buku Teks
Bartle, Robert Gardner, 1927-
Scott, Foresman, 1968
Buku Teks
Sherwood, G.E.F.
Prentice-Hall, 1946
Buku Teks