Gates, Jean Key
McGraw-Hill, 1974
Buku Referensi
Wild, John J.
Irwin/McGraw-Hill, 2000
Buku Teks
Thompson, Anthony
UNESCO, 1983
Buku Referensi
Parker, Christopher Charles
Butterworths, 1960
Buku Teks
Raymond H. Shove ... [and others]
University of Minnesota Press, 1963
Buku Teks