Coulshed, Veronica, author
Macmillan, 1988
Buku Teks
Ferguson, Elizabeth A., author
J.B. Lippincott, 1975
Buku Teks
Dobelstein, Andrew W., author
Wadsworth, 2003
Buku Teks
Farley, O. William, 1934-, author
Pearson Education, 2012
Buku Teks
Marier, Roger, author
UNESCO, 1953
Buku Teks