Basel : Verlag fur Recht und Gesellschaft A.G.
Majalah, Jurnal, Buletin
Taine, H
Paris Hachette 1892
Buku Teks
Cambridge : The American Academy of Arts and Sciences
Majalah, Jurnal, Buletin
Jasinski, Rene
Paris Boivin c1947
Buku Teks
Pretoria : University van Pretoria
Majalah, Jurnal, Buletin