1. On a problem concerning the stability in the large of dynamical systems. Uspekhi Mat;Aizerman;Nauk,1949
2. Barbashin, E. and Tabueva, V. (1969). Dynamical systems with cylindrical phase space (in Russian). Nauka, Moscow.
3. Phase-Locked Loops: Design, Simulation and Application;Best,2007
4. Tutorial on dynamic analysis of the Costas loop;Best;IFAC Annual Reviews in Control,2016
5. Phase-Locked Loops;Blanchard,1976