Gatekeeping theory/ 
Shoemaker,Pamela J. 
 - 1st ed. 
 - New York:  Routledge,  2009. 
 - 173 p. 
<br/><br/><label>ISBN: </label>9780415981385 
<br/><br/><label>Dewey Class. No.: </label>302.23  / SHO/G