[1] Бopyвкa O.: Teopuя глoбaлъныx cвoücmв oбыкнoвeнныx лuнeйныx дuффepeнцuaльныx ypaвнeний вmopoгo nopядкa. Дифф. ypaвнeния, Toм. XII, 1976, 1348-1383.
[2] Borůvka O.:
Linear Differential Transformations of the Second Order. The English Universities Press, London, 1971.
MR 0463539
[3] Wintner A.:
On the nonexistence of conjugate points. Amer. J. Math. 73, 1961, 368-380.
MR 0042005
[4] Krbiľa J.: Diferenciálne rovnice druhého rádu a kvadratické funkcionály. Habilitačná práca. Žilina, 1974.
[5] Leighton W., Morse M.:
Singular quadratic functionals. Trans. Ameг. Math. Soc. 40, 1936, 252-286.
MR 1501873 |
Zbl 0015.02701
[6] Krbiľa J.: Pure disconjugate homogeneous linear differential equations of the second order. Zborník ved. prác DF VŠLD Zvolen, 1972, 241-248.