Gabriel, P. and Zisman, M. <br/><br/>
Calculus of Fractions and Homotopy theory 

 - New York  Springer-Verlag  1967 
 - 168 
<br/><br/><label>Publisher. No.: </label> Bangalore Book Bureau 
<br/><br/><label>Subjects--Personal Names: </label> Mathematics 
<br/><br/><label>Subjects--Topical Terms: </label><br/>Mathematics