[1] O. Borůvka:
Lineare Differentialtransformationen 2. Ordnung. VEB Deutsch. Verlag Wiss. Berlin 1967.
MR 0236448
[2] R. Freedman: Oscillation theory of systems of ordinary differential equations. Thesis, PINY 1979.
[3] H. Guggenheimer:
On focal points and limit behavior of solutions of differential equations. Arch. Math. (Brno) 14 (1978) 139-144.
MR 0508430
14] H. Guggenheimer:
Geometric theory of differential equations, III. Second Order Equations of the Reals. Arch. rat. Mech. Anal. 41 (1971) 219-240.
MR 0357939
[7] A. C. Peterson:
On the monotone nature of boundary value functions for n-th order differential equations. Canad. Math. Bull. 15 (1972) 253-258.
MR 0310324 |
Zbl 0236.34019