ANDREY UTENYSHEV, KONSTANTIN BOGENKO, VALERIY TKACHEV, O. K. S. A. 3.2.1. Synthesis, crystal and molecular structure of catena-(bis(µ1-oxalic acid)-µ3-hydrogen oxalate-di-aqua-sodium(I)). Communications in Inorganic Synthesis, v. 3, n. 2, 11.