1. Elliptic singular integro-differential operators;Agranovich;Russian Math. Surveys,1965
2. Theory of Oscillations;Andronov,1949
3. Ordinary Differential Equations;Arnold,2006
4. On conditions for non-linear stability of plane stationary curvilinear flows of an ideal fluid;Arnold;Sov. Mat. Dokl.,1965
5. On the behavior of special classes of ultraspherical expansions;Askey;J. Anal. Math.,1965