Hall, W. S.: The Rayleigh and van der Pol wave equations, some generalizations.
(English).
In:
Fábera, Jiří (ed.): Equadiff IV.
Czechoslovak Conference on Differential Equations and Their Applications. Proceedings, Prague, August 22-26, 1977.
Springer-Verlag, Berlin, 1979.
pp. [130]-138