American-British Dictionary
American-Canadian-British Dictionary
British dictionary: American guide to speak British, words and expressions
that differ in their usage.
Newfoundland English dictionary (Canada)
American English by Gilbert Tucker (1921)
Dictionary of Americanisms being
a glossary of words supposed to be peculiar to the United States and the dominion of Canada, by Sylva Clapin (1902) 
Americanisms, old and new,
Dictionary of words, phrases and colloquialisms peculiar to the United States, British America, the West Indies..., their derivation, meaning
and application, together with numerous anecdotal, historical, explanatory and folk-lore notes, by John Farmer (1889)
The American Slang Dictionary by James Maitland
(1891)
Americanisms, the English
of the New World, by Maximilian Schele de Vere (1872)
Dictionary of Americanisms by John Russell
Bartlett (1859)
Glossary of supposed Americanisms collected by
Alfred Elwyn (1859)
books about American language & Americanisms: Google
books & Internet
archive
The American
language, a preliminary inquiry into the development of English in the United States, by Henry Louis Mencken
(1919) 
United States: maps, symbols, heritage & documents
Canada: maps, symbols, heritage & documents
English dictionary (British & American) & English language
American, Australian, Irish
English