Willis, F. R. (1977). Western civilization: An urban perspective (2nd.ed.). D.C.Heath and Co..
Dyfyniad Arddull ChicagoWillis, F. Roy. Western Civilization: An Urban Perspective. 2nd.ed. Lexington: D.C.Heath and Co., 1977.
Dyfyniad MLAWillis, F. Roy. Western Civilization: An Urban Perspective. 2nd.ed. D.C.Heath and Co., 1977.
Rhybudd: Mae'n bosib nad yw'r dyfyniadau hyn bob amser yn 100% cywir.