1. Beesack, P.R., D.S. MitrinoviĆ and P.M. VASIĆ, Integral inequalities, (the manuscript not achieved and not published).
2. Ewing, G.M., “Calculus of Variations with Applications,” New York, 1969.
3. Young, L.C., “Calculus of Variations and Optimal Control Theory,” Philadelphia-London-Toronto, 1969.
4. Hardy, G.H., J.E. Littlewood, and G. PÓlya, “Inequalities,” Cambridge, 1934, 1952.
5. Florkiewicz, B. and A. Rybarski, Some integral inequalities of Sturm-Liouville type, Colloq. Math. 36 (1976), 127–141.