Capogna, L., et al <br/><br/>
Introduction to the Heisenberg group & the sub-riemannian isoperimetric problem 
L. Capogna, et al 
 - Basel  Birkhauser-Verlag  2007 
 - xvi  223 
 - Progress in mathematics 259 .
<br/><br/><label>ISBN: </label>9783764381325 
<br/><br/><label>Dewey Class. No.: </label>8.04+8.05  / CAPO