Preparation, characterization, and decay of einsteinium(II) in the solid state J.R. Peterson, D.D. Ensor, R.L. Fellows, R. G. Haire et J. P. Young J. Phys. Colloques, 40 C4 (1979) C4-111-C4-113 DOI: 10.1051/jphyscol:1979435