Negoita, Constantin Virgil
The Benjamin Cumming Pub., 1985
Buku Teks SO
Alty, J.L.
NCC Publications, 1984
Buku Teks SO
Chapman and Hall , 1990
Buku Teks SO
Siddall, James N.
Marcel Dekker, 1990
Buku Teks SO
edited by, Frederick Hayes-Roth, Donald A. Waterman and Douglas Lenat
Addison-Wesley, 1983
Buku Teks SO