@article{622klimeck2001, author = "Gerhard Klimeck and R. Bowen and Timothy Boykin", title = "A tiger by the tail: the momentum operator in tight-binding", year = "2001", note = "March Meeting of American Physical Society, March 12-16, Seattle, WA (2001)", url = "http://www.aps.org/meet/MAR01/baps/abs/S4430015.html", }