中国科学院数学与系统科学研究院期刊网
AMS
Classification of (2, 2)-Stable Unfoldings of Map Germs with Codimensions ≤ 4
Xiong Jianfei
Acta Mathematica Sinica . 1996, (4): 415 -432 .  DOI: 10.1007/BF02106796