Gupta, Ashit Das. Degree level differential equations / by Ashit Das Gupta,Surya Bhushan Prasad and Ram Sharan Prasad. - 1st ed / - Patna : Bharati Bhawan(Publishers & Distributors) , 1994 - vi,168p ; Subjects--Topical Terms: Orthogonal Trajectory Dewey Class. No.: B33 / N7