Sharma, Ram Sharan
Indian feudalism : C. A. D. 300-1200
Macmillan, 1980
Buku Teks
Stephenson, George E.
Power technology / George E. Stephenson
Delmar, 1986
Buku Teks
Milsom, S.F.C.
The legal framework of english feudalism / S.F.C. Milsom
Cambridge Uiversity Press, 1976
Buku Teks
Golden, Harry
Carl Sanburg
World Pub., 1961
Buku Teks SO
Stephenson, Reginald J.
Mechanics and properties of matter/ Reginald J. Stephenson
John Wiley & Sons, 1969
Buku Teks