@book{20540,
	author = {Hebb, Bertha Yell.},
	title = {Credit for professional improvement of teachers.},
	publisher = {Govt. print. off.,},
	year = {1922]},
	series = {[U.S.] Bureau of education.  Teacher's leaflet},
	address = {[Washington,},
	note = {Caption title.}
}