“Royal Mail”, a centenary history of the Royal Mail Line 1839-1939
Trade and Travel Publications, 
A Dictionary, Theoretical, and Historical, of Commerce and Commercial Navigation – J R McCulloch
London, printed for Longman, Brown, Green…., 1845
A Merchant Fleet in War, Alfred Holt & Co. 1939-1945
by S.W. Roskill
the story of the Blue Funnel ships and other vessels in the Alfred Holt group during world war 2
Advent of Steam, the merchant steamship before 1900
Robert Gardiner (editor)
a volume in Conway’s authoritative “History of the Ship” series.
Alaska Steam, a pictorial history of the Alaska Steamship Company
by Lucile McDonald
Alaska Geographic, 1984.