Devillers, M., Ladrière, J., & Apers, D. (1987). Mossbauer Study of Fe-57-doped Simple and Mixed Dihydrated Oxalates of Bivalent Metals (m=mg, Mn, Fe, Co, Ni, Zn). Inorganica Chimica Acta, 126(1), 71-77. https://doi.org/10.1016/S0020-1693(00)81242-6 (Original work published 1987)