Ragan, D. M. (1968). Structural geology: Fourth Edition. John wiley.
Dyfyniad Arddull ChicagoRagan, Donal M. Structural Geology: Fourth Edition. New york: John wiley, 1968.
Dyfyniad MLARagan, Donal M. Structural Geology: Fourth Edition. John wiley, 1968.
Rhybudd: Mae'n bosib nad yw'r dyfyniadau hyn bob amser yn 100% cywir.