00300nam a2200109Ia 450000500170000000800410001708200150005810000170007324500500009026000420014030000080018220260225044756.0260224s9999||||xx |||||||||||||| ||und||  a517.38 AYR  aFrank Ayres  0aTheory and problems of differntial equations   aNew York: McGraw-Hill Book Co. c1972  a295