1. Research Problems in Function Theory;Hayman,1967
2. Differential equations of infinite order, hyperdirichlet series and entire functions of bounded index;Lepson,1968
3. Differential inequalities and local valency;Hayman;Pacific J. Math.,1973
4. Entire functions satisfying a linear differential equation;Shah;J. Math. Mech.,1968
5. Entire functions satisfying a linear differential equation;Fricke;Indag. Math.,1975