@article{article9c12198f,
title   = {Two members of the bisphosphonate class of drugs: a zwitterion and a molecular compound},
author = {Fernández, Daniel and Vega, Daniel and Ellena, Javier},
year = {2003},
doi = {10.1107/s0108270103007649},
journal   = {Acta Crystallographica C}
}