Hakl, Robert and Zamora, Manuel. "Existence of a solution to the Dirichlet problem
associated to a second-order differential equation with
singularities: The method of lower and upper functions"
Georgian Mathematical Journal, vol. 20, no. 3, 2013, pp. 469-491.
https://doi.org/10.1515/gmj-2013-0030Hakl, R. & Zamora, M. (2013). Existence of a solution to the Dirichlet problem
associated to a second-order differential equation with
singularities: The method of lower and upper functions.
Georgian Mathematical Journal,
20(3), 469-491.
https://doi.org/10.1515/gmj-2013-0030Hakl, R. and Zamora, M. (2013) Existence of a solution to the Dirichlet problem
associated to a second-order differential equation with
singularities: The method of lower and upper functions. Georgian Mathematical Journal, Vol. 20 (Issue 3), pp. 469-491.
https://doi.org/10.1515/gmj-2013-0030Hakl, Robert and Zamora, Manuel. "Existence of a solution to the Dirichlet problem
associated to a second-order differential equation with
singularities: The method of lower and upper functions"
Georgian Mathematical Journal 20, no. 3 (2013): 469-491.
https://doi.org/10.1515/gmj-2013-0030Hakl R, Zamora M. Existence of a solution to the Dirichlet problem
associated to a second-order differential equation with
singularities: The method of lower and upper functions.
Georgian Mathematical Journal. 2013;20(3): 469-491.
https://doi.org/10.1515/gmj-2013-0030Copied to clipboard
satisfy the local Carathéodory conditions and may have singularities
both in the time (for 
and 
) and the phase
(for 
and 
) variables. Sufficient conditions for the solvability of
the above-mentioned problem are established.