@article{articlee15798d5,
title   = {Existence of orthogonal geodesic chords on Riemannian manifolds with concave boundary and homeomorphic to the -dimensional disk},
author = {Giambó, Roberto and Giannoni, Fabio and Piccione, Paolo},
year = {2010},
doi = {10.1016/j.na.2010.03.019},
journal   = {Nonlinear Analysis: Theory, Methods & Applications}
}