Quad-4: a computer program for evaluating the seismic respo-nse of soil structures by variable damping finite element p-rocedures / by I.M. Idriss...[et al.] 

 - Berkeley, Calif. : University of California, College of Engineering 
 - 72 p. 
 - Report ; No. UCB /EERC 73-16. .
<br/><br/> "A report on research sponsored by the National Science Fou-ndation".