00297nam a2200121Ia 4500082002000000100001800020245003900038260003500077300001500112490003800127500000500165700000500170  a515.24bW638.IT  aWidder, D. V.  aIntroduction to transform theoryb  aNew YorkbAcademic Pressc1971  axiv, 253p.  aPure and Applied Mathematicsv 42  a  a