@book{40798,
	author = {Abercrombie, David.},
	title = {Problems and principles in language study /},
	publisher = {Longmans,},
	year = {1963 [Impression 1967]},
	address = {London :},
	edition = {2nd ed.},
	note = {Earlier ed. (1956) has title: Problems and principles : studies in the teaching of English as a second language.}
}