Cohen, Louis, 1928- Research methods in education / Louis Cohen and Lawrence Manion. - 3rd ed. - London ; New York, NY : Routledge, 1989. - xxii, 413 p. : ill. ; 22 cm. ISBN: 0415036488 (U.S.) LCCN: 88039815 LC Class. No.: LB1028 .C572 1989 / .C572 1989 Dewey Class. No.: 370/.7/8