Šeda, V.: An application of Green's function in the differential equations.
(English).
In:
Šeda, Valter (ed.): Differential Equations and Their Applications.
Proceedings of the Conference held in Bratislava in September 1966.
Slovenské pedagogické nakladateľstvo, Bratislava, 1967.
pp. 221-235
Coddington, E. A.: Formally normal ordinary differential operators.
(English).
In:
Šeda, Valter (ed.): Differential Equations and Their Applications.
Proceedings of the Conference held in Bratislava in September 1966.
Slovenské pedagogické nakladateľstvo, Bratislava, 1967.
pp. 65-72