Boltyanskii, V. G. <br/><br/>
Envelopes 
V. G. Boltyanskii 
 - Oxford  Pergamon Press  1964 
 - ix,76p.  22cm. 
 - Popular Lectures in Mathematics; v.12 .
<br/><br/><label>Subjects--Topical Terms: </label><br/>Envelopes (Geometry)
<br/><br/><label>LC Class. No.: </label>MATH QA621.B65