中国科学院数学与系统科学研究院期刊网
Landau's Theorems for Certain Biharmonic Mappings
Ming Sheng LIU, Zhi Wen LIU, Yu Can ZHU
Acta Mathematica Sinica, Chinese Series . 2011, (1): 69 -80 .  DOI: 10.12386/A2011sxxb0008