Boyle, John Andrew, author
Luzac & Company, 1949
Buku Referensi
Palmer, E.H., author
Routledge & Kegan Paul, 1956
Buku Referensi
Ram Narain Lal Publisher, 1947
Buku Referensi
Steingass, F., author
Kegan Paul, Trench, Trubner & Co., 1947
Buku Referensi
Levy, Reuben
Hutchinson's University Library, 1951
Buku Teks