editor, John C. McCaslin
PennWell Publishing , 1990
Buku Referensi
Stokes, Adrian V.
Wildwood House, 1986
Buku Referensi
Pandey, A.K., author
Anmol Publications, 1992
Buku Referensi
Field Enterprises Educational Corporation, 1963
Buku Referensi
Rhodes, V. James
Grid Publishing, Inc, 1978
Buku Teks