Reynolds, Lloyd G.
Prentice-Hall, 1998
Buku Teks SO
Reynolds, Lloyd G.
Prentice-Hall, 1982
Buku Teks SO
Reynolds, Lloyd G.
Prentice-Hall, 1959
Buku Teks SO
Flanagan, Robert J.
Scott, Foresman, 1984
Buku Teks SO
Coombs, H.C. [Herbert Cole], 1906-
Macmillan, 1981
Buku Teks SO