Hampel, Clifford A.
Van Nostrand Reinhold, 1982
Buku Referensi
Prytherch, Ray, compiler
Gower, 2000
Buku Referensi
compiled by Ray Prytherch
Gower, 1990
Buku Referensi
Seoul Donga il bo sa, 2006
Buku Referensi
Andersen, Dines
Copenhagen: Gyldendalske Boghandel, 1907
Buku Teks