[1]
J. Castañeda-Contreras, V. Marañón-Ruiz, M. Meneses-Nava, H. Pérez- Ladrón de Guevara, R. Rodríguez Rojas, and R. Chiu-Zárate, Properties of Er$_2$O$_3$ nanoparticles synthesized by a modified co-precipitation method, Rev. Mex. Fís. 61, (2015).