 |
| |||
| 自然階層 (A hiearchy in which at every level there is a one-to-many relationship between members in that level and members in the next lower level) | |||
|
| |||
| 自然階層 (A hiearchy in which at every level there is a one-to-many relationship between members in that level and members in the next lower level) | |||
