Artikel Jurnal
Patrick, John
Macmillan Publishing Company, 1984
Buku Teks
Todd, Lewis Paul, author
Harcourt, Brace & World, 1961
Buku Teks
Todd, Lewis Paul, author
Harcourt Brace Jovannovich, 1972
Buku Teks
Harsja W. Bachtiar, 1934-, author
FSUI , 1972
Buku Teks