1. Distributed Parameter Process Dynamics;Cohen,1961
2. The Dynamics of Automatic Control Systems;Popov,1962
3. Absolute Stability of Nonlinear Systems of Automatic Control;Popov;Automation and Remote Control,1961
4. The Solution of a New Stability Problem for Controlled Systems;Popov;Automation and Remote Control,1963
5. Frequency Domain Stability Criteria;Brockett,1965