Swarup, D., author
Rakesh K. Rastogi for Rastogi, 1981
Buku Teks
Higgins, Raymond.A.
E. Arnold,, 1980
Buku Teks
Rollason, E.C.
Edward Arnold, 1978
Buku Teks
W.T. Frier, B. S.
mcGraw-Hill Company, 1952
Buku Teks
Rosenqvist, Terkel, author
McGraw-Hill, 1983
Buku Teks