@article{701672,
     title = {A remark on natural quantum Lagrangians and natural generalized Schr\"odinger operators in Galilei quantum mechanics},
     booktitle = {Proceedings of the 20th Winter School "Geometry and Physics"},
     series = {GDML\_Books},
     publisher = {Circolo Matematico di Palermo},
     address = {Palermo},
     year = {2001},
     pages = {117-128},
     mrnumber = {MR1826684},
     zbl = {0983.81027},
     url = {http://dml.mathdoc.fr/item/701672}
}

Janyška, Josef. A remark on natural quantum Lagrangians and natural generalized Schrödinger operators in Galilei quantum mechanics, dans Proceedings of the 20th Winter School "Geometry and Physics", GDML_Books,  (2001), pp. 117-128. http://gdmltest.u-ga.fr/item/701672/