Prytherch, Ray
Gower, 2000
Buku Referensi
compiled by Ray Prytherch
Gower, 1990
Buku Referensi
Harrod, Leonard Montague
England : Gower Pub, 1987,
Buku Referensi
Stein, J. Stewart
Wiley, 1980
Buku Referensi
Stein, J. Stewart
Wiley, 1980
Buku Referensi