Paolo Strazzolini, Alberto Gambi, Angelo G. Giumanini and Hrvoj Vancik (1998). "The reaction between ethanedioyl (oxalyl) dihalides and Ag2C2O4: a route to Staudinger's elusive ethanedioic (oxalic) acid anhydride". J. Chem. Soc., Perkin Trans. 1.{{cite journal}}: CS1 maint: multiple names: authors list (link)