@book{28560,
	author = {Lefschetz, Solomon},
	title = {Differential equations},
	publisher = {Dover Publications},
	year = {1977.},
	address = {New York},
	edition = {2d ed.},
	note = {"Unabridged republication of the second (1963) edition of the work originally published by Interscience Publishers in 1957 as volume VI of the Interscience pure and applied mathematics series."}
}