[1] I. Bihari:
Oscillation and monotonity theorems concerning non-linear differential equations of the second order. Acta Mathematica Academiae Scientiarum Hungaricae, Vol. 9 (1958), pp. 83-104.
MR 0095321
[2] O. Borůvka: Lineare differentialtransformationen 2. ordnung. Berlin, 1967.
[3] L. Lorch:
Comparison of two formulations of Sonin's theorem and of their respective applications to Bessel functions. Studia Scientiarum Mathematicarum Hungarica, Vol. 1 (1966), pp. 141-145.
MR 0204723 |
Zbl 0148.30101