中国科学院数学与系统科学研究院期刊网
Maps on Self-Adjoint Operators Preserving Numerical Range of Products up to a Factor
Kan HE, Jin Chuan HOU, Dolinar GREGOR, Kuzma BONJA
Acta Mathematica Sinica, Chinese Series . 2011, (6): 925 -932 .  DOI: 10.12386/A2011sxxb0093