Rothstein, Andrew
Penguin Books , 1950
Buku Teks
Riasanovsky, Nicholas V.
Oxford University Press, 1963
Buku Teks
edited by Harry Daniels
Routledge, 2005
Buku Teks
Garder, Michel
Frederick A. Praeger, 1966
Buku Teks
Rauch, Georg von
Frederick A. Preager , 1957
Buku Teks