I use several reference works for the information provided on these pages, as follow:

Lloyds Register of Shipping Ocean Ships - David Hornsby Jane's Merchant Ships 1986
Soviet Merchant Ships - Ambrose Greenway Comecon Merchant Ships - Ambrose Greenway
British Warships & Auxiliaries - Mike Critchley Marine News
ShipWatch Directory Ferries of the British Isles & Northern Europe -
Nick Widdows