Coombs, Philip H.
Rajawali, 1984
Buku Teks
Coombs, Philip H.
Johns Hopkins University Press, 1974
Buku Teks
Coombs, Philip H.
John Hopkins University Press, 1988
Buku Teks
Gould, W.T.S.
John Wiley, Longman Scientific, 1993
Buku Teks SO
edited by Keith Watson
Croom Helm, 1982
Buku Teks