Torak, Lynn J <br/><br/>
A modular finite-element model (modfe) for areal and axisymmetric gound-water-flow problems, part 3 : design philosophy and programming details / 
by Lynn J. Torak 
 - Washington :  U.S. Government Printing Office,  1993 
 - 243 p. :  ill. ; 
<br/><br/> Techniques of water-resources investigations of the United States Geological Survey