00294nam a2200109 a 450000500170000002000150001708200180003210000200005024500440007026000440011430000260015820251203110046.0  a0486659739  a515.2433bDAV  aDavis, Harry F.  aFourier series and orthogonal functions  aNew YorkbDover Publcations, INC.c1989  axii,403p.c23 cm P.B.