@article{GDZPPN002355485,
title = {Non-hyperbolic closed geodesics.},
journal = {Mathematica Scandinavica},
volume = {44},
year = {1979},
pages = {135-148},
zbl = {0414.53037},
url = {http://dml.mathdoc.fr/item/GDZPPN002355485}
}
Thorbergsson, Gudlaugur. Non-hyperbolic closed geodesics.. Mathematica Scandinavica, Tome 44 (1979) pp. 135-148. http://gdmltest.u-ga.fr/item/GDZPPN002355485/