Naimark, N.A. <br/><br/>
Linear differential operators - P.I  elementary theory of linear differential operators 
by M.A. Naimark, tr. by E.R. Dawson 
 - London  Georger G. Harrap & Company  1968 
 - xiii, 144p. 
<br/><br/><label>Dewey Class. No.: </label>515.35  / N682.1