Citation: Pushcharovskii, D.Yu.; Dago, A.M.; Belov, N.V.; Pobedimskaya, E.A. (1980). Crystal structure of erbium germanogermanate Er4 Ge3 O9 ((O H), F)6. Crystal-chemical features of the structural type Tr4 (Ge(VI) Ge2(IV) O9) ((O H), F)6 (Tr=Er-Lu). Doklady Akademii Nauk SSSR, 251, pp. 354-357.