Necessary and sufficient conditions for oscillation of neutral equation Purna Candra Das — 1994 Czechoslovak Mathematical Journal
Oscillation of odd order neutral delay differential equation Purna Candra Das — 1995 Czechoslovak Mathematical Journal
Existence and stability of measure differential equations Purna Candra Das; Rishi Ram Sharma — 1972 Czechoslovak Mathematical Journal
On the zeros of solutions of nonhomogeneous third order differential equations N. Parhi; Purna Candra Das — 1991 Czechoslovak Mathematical Journal
Oscillation and nonoscillation of nonhomogeneous third order differential equations N. Parhi; Purna Candra Das — 1994 Czechoslovak Mathematical Journal