The Royal Canadian Navy Postal History 1939-45, Vol. 1
The Royal Canadian Navy Postal History 1939-1945, Vol. 1, 1993 by Percy G. Colbeck & Maurice F. Hampson. DB/N Naval Censorship numbers at Fleet Mail Offices and aboard ships, Fleet mail numbers, NPO numbers, Shore establishments, blackout and other cancellations and markings. Cerlox, 82 pp.