Collison, R. L. (1960). Library assistance to readers ([3rd ed., rev. and enl.].). Lockwood.
Dyfyniad Arddull ChicagoCollison, Robert Lewis. Library Assistance to Readers. [3rd ed., rev. and enl.]. London: Lockwood, 1960.
Dyfyniad MLACollison, Robert Lewis. Library Assistance to Readers. [3rd ed., rev. and enl.]. Lockwood, 1960.
Rhybudd: Mae'n bosib nad yw'r dyfyniadau hyn bob amser yn 100% cywir.