column
![](/style/images/custom/toleft.png)
![](/style/images/custom/toright.png)
1989, 10(2): 89-96.
1989, 10(2): 129-132.
1989, 10(2): 133-138.
1989, 10(2): 139-142.
1989, 10(2): 143-153.