Apel, Willi,  1893-1988. <br/><br/>
Gregorian chant. 

 - Bloomington,  Indiana University Press  [1958] 
 - xiv, 529 p.  8 facsims., music.  24 cm. 
<br/><br/> Includes chapters on the Ambrosian chant, by R. Jesson and the Old Roman chant, by R. J. Snow. 
<br/><br/>Bibliography: p. xiii-xiv. 
<br/><br/><label>LCCN: </label>57010729 
<br/><br/><label>Subjects--Topical Terms: </label><br/>Gregorian chants--History and criticism.
<br/><br/><label>LC Class. No.: </label>ML 3082  / .A64