@book{137799,
	author = {Wheldon, Harold J. and Thirkettle, G. L.},
	title = {Wheldon's business statistics and statistical method /},
	publisher = {Macdonald & Evans,},
	year = {1968.},
	address = {London :},
	edition = {6th ed.},
	note = {First ed. published in 1936.}
}