1. Functional Analysis and Semi-Groups;Hille,1948
2. Functional Analysis and Semi-Groups;Hille,1957
3. Remark on the Landau-Kallman-Rota inequality;Hille;Aequationes Mat.,1970
4. On the inequality ‖f′‖2 ⩽ 4 ‖f‖ ‖f″‖;Kallman,1970
5. Remark on the Landau inequality;Kurepa;Aequationes Math.,1970