@book{30305,
	author = {Clayton, Albert Edmund, and Hancock, N. N.},
	title = {The performance and design of direct current machines /},
	publisher = {Pitman,},
	year = {1959 (1974 reprint)},
	address = {London :},
	edition = {3rd ed. rev. by the author in collaboration with N.N. Hancock.},
	note = {Previous ed. 1938.}
}