Oleinik O A <br/><br/>
Second order equations with nonnegative characteristic form 

 - New York       American Mathematical Society        1973 
 - vii, 259p.  cm. 
<br/><br/><label>Standard No.: </label>22997 
<br/><br/><label>Source: </label> Textual 
<br/><br/><label>Subjects--Topical Terms: </label><br/> Boundary value problems<br/>Differential equations
<br/><br/><label>Dewey Class. No.: </label>B334,7,2:7, L3