2IAN WES TBURY and NEIL J.WILKOF.SCIENCE, CURRICULUM, AND LIBERAL EDUCATION.The University of Chicago Press: CHICAGO & LONDON, 1978:69-70,71-72,81,81.
3Joseph J.Schwab.The Teaching of Science.The Teaching of Science as Enquiry.Harvard Universi- ty Press, Cambridge, Massachusetts, 1962:13-14,49,49,49- 50,50,50-51.
4Charles F.Madden.Talks with scientists .southern Illi- nois university press.feffer & simons, inc.London and Amster- dam, 1968,13.