@article{articled1a98ce0,
title   = {A systolic inequality for geodesic flows on the two-sphere},
author = {Abbondandolo, Alberto and Bramham, Barney and Hryniewicz, Umberto L and Salomão, Pedro Antônio Santoro},
year = {2017},
doi = {10.1007/s00208-016-1385-2},
journal   = {Mathematische Annalen}
}