Crystal structure of diaquadisodium [l-(ethoxy-hydroxy-phosphoryl)- 1-hydroxy-ethyl]phosphonic acid diethyl ester, Na2(H2O)2[(C2H5OPO2)2C(CH3)OH], a pro-drug derivative for etidronate - Monteil M. (Zeitschrift für Kristallographie - New Crystal Structures, 2005)