@book{19747,
	author = {Ayres, Leonard Porter,},
	title = {Constant and variable occupations and their bearing on problems of vocational education.},
	publisher = {Division of Education, Russell Sage Foundation},
	year = {[1914]},
	series = {[Russell Sage Foundation, New York.  Division of Education.  Pamphlets] E136},
	address = {New York City,}
}