Peter, Laurence J.
Erlangga, 1988
Buku Teks SO
Cassidy, Carlene M.
South Western Cengage Learning, 2011
Buku Teks SO
Clinch, Peter
Aslib, 2000
Buku Teks SO
Sanderson, Peter C.
Pan Books, 1972
Buku Teks SO
Sanderson, Peter C.
Pan Books , 1969
Buku Teks SO