@article{articleaeb2fc04,
title   = {On the singularities of the exponential map in infinite dimensional Riemannian manifolds},
author = {Biliotti, Leonardo and Exel Filho, Ruy and Piccione, Paolo and Tausk, Daniel Victor},
year = {2006},
doi = {10.1007/s00208-006-0001-2},
journal   = {Mathematische Annalen}
}