Timings, R.L. (Roger Leslie), 1927-, author
Longman, 1988
Buku Teks
Eide, Arvid R., author
McGraw-Hill, 2002
Buku Teks
Levinson, L., author
Peace Publishers, [date of publication not identified]
Buku Teks
Ghezzi, Carlo, author
Prentice Hall International, 1991
Buku Teks
Rizzoni, Giorgio, author
McGraw-Hill, 2009
Buku Teks