Mulgan, John
Clarendon Press, 1967
Buku Teks
Harrap Book Limited, 1991
Buku Referensi
edited by Lesley Brown
Clarendon Press, 1993
Buku Referensi
edited by Louis G. Locke, William M. Gibson, George Arms
Holt, Rinehart and Winston, 1959
Buku Teks
Turville-Petre, Thorlac
Blackwell Publishing, 2007
Buku Teks