Brandt, Conrad
George Allen and Unwin, 1959
Buku Teks
Hirth, F.
The Statistical Department of The in Pectorate General of Customs, 1888
Buku Referensi
Ho Kan-Chih
Peking: Foreign Language Press, 1959
Buku Teks
Bianco, Lucien
Stanford University Press, 1971
Buku Teks
Isaacs, Harold R.
Standford University Press, 1951
Buku Teks