Henry, Nelson B.
University of Chicago, 1957
Buku Teks
edited by Nelson B. Henry
University of Chicago Press, 1952
Buku Teks
Purdue University, 1963
Buku Teks
Pitman Pub. Co., 1960
Buku Teks
edited by Susan Higgins, Meta Brett
Longman, 1984
Buku Referensi