Chaurasia, V. B. L. Goyal, M. C. Verma R. K. Tyagi, Sanjeev Jaipur Indus Valley 2006 v.1: v.p. by V. B. L. Chaurasia...[et.al.] Mathematics Differential equations, partial 515.35 G74D 9788188719327 20211209120104.0 150414