中国科学院数学与系统科学研究院期刊网
AMS
Additive Maps Preserving Nilpotent Operators or Spectral Radius
Zhao Fang BAI, Jin Chuan HOU
Acta Mathematica Sinica . 2005, (5): 1167 -1182 .  DOI: 10.1007/s10114-005-0503-y