Barnard, David T.
Wm. C. Brown Publisher, 1988
Buku Teks
Nyhoff, Larry, author
Prentice-Hall, 1997
Buku Teks SO
Etter, Delores Maria, 1947-, author
Benjamin/Cummings, 1987
Buku Teks SO
Golde, Hellmut, author
Macmillan, 1966
Buku Teks
Page, Clive, author
Elex Media Komputindo, 1988
Buku Teks