U.S. National Archives and Records Service. General Services Administration. Records Management Division. (1955). Records management handbook: Managing correspondence _ plain letters. s.n.].
Dyfyniad Arddull ChicagoU.S. National Archives and Records Service. General Services Administration. Records Management Division. Records Management Handbook: Managing Correspondence _ Plain Letters. [S.l: s.n.], 1955.
Dyfyniad MLAU.S. National Archives and Records Service. General Services Administration. Records Management Division. Records Management Handbook: Managing Correspondence _ Plain Letters. s.n.], 1955.
Rhybudd: Mae'n bosib nad yw'r dyfyniadau hyn bob amser yn 100% cywir.