12.Wei YT, Yu JH, Chen JK. Object-oriented approach to the finite element programming: design of element procedure. Journal of Sichuan University (Engineering Science Edition) 2001; 33(3): 9–12. [魏泳涛、于建华、陈君楷,面向对象有限元程序设计—单元过程设计 [J],四川大学学报:工程科学版,2001,33(3):912]