[1]
A. Myshkis, D. Bainov, y M. Dimitrova, «Oscillatory and Asymptotic Properties of the Solutions of a Class of Operator-Differential Equations», Rev. mat. complut., vol. 7, n.º 2, p. 309, ene. 1994, doi: https://doi.org/10.5209/rev_REMA.1994.v7.n2.17747