@book{21532,
	author = {Karnakov, Boris Mikhailovich and Krainov, Pavlovich },
	title = {WKB Approximation in Atomic Physics},
	publisher = {Springer Berlin Heidelberg},
	year = {2013},
	address = {Heidelberg, Berlin},
	url = {http://doi.org/10.1007/978-3-642-31558-9}
}