Risk, Thomas Marion,   1885- <br/><br/>
Principles and practices of teaching in secondary schools / 
by Thomas M.Risk. 
 - 4th ed. 
 - New York :  American Book Co.,  1968 
 - 517 p. :   illus. ;   25 cm. 
<br/><br/><label>Subjects--Topical Terms: </label><br/>Education--Experimental methods<br/>Education, Secondary<br/>Educational psychology