Warren, J. W. Understanding force : an account of some aspects of teaching the idea of force in school,college and university courses in engineering,m athematics and science / J. W. Warren - London : John Murray , 1979 - vi, 64 p. : ill. ; 22 cm. Subjects--Topical Terms: Force and energy --Study and teaching------ Dewey Class. No.: 531.11307 WAR