[1] М. А. Красносельский С. Г. Крейн:
О принципе усреднения в нелинейной механике. Успехи математических наук, 10: 3 (1955), 147-152.
MR 0071596 |
Zbl 1229.11009
[2] J. Kurzweil:
Generalized Ordinary Differential Equations and Continuous Dependence on a Parameter. Czechoslovac Mathematical Journal, 7 (82), 1957, 418-449.
MR 0111875 |
Zbl 0090.30002
[3] G. Sansone: Equazioni differenziali nel campo reale. Bologna 1948.
[4] E. A. Goddington N. Levinson: Theory of Ordinary Differential Equations. 1955.