@article{Maciejewski:2008,
author = "A. Maciejewski and M. Przybylska and H. Yoshida",
title = "Necessary conditions for super-integrability of Hamiltonian systems",
journal = "Physics Letters A",
volume = "Vol. 372",
number = "no 34",
pages = "5581--5587",
year = "2008",
}