In the previous example, the author information is in a lowerlevelnode.
在上面这个例子中，作者信息位于一个级别较低的节点上。
2
The index contains a node that is a small array of Pointers to the lowerlevel.
索引包含一个节点，该节点是一个小型的指针数组，这些指针又指向更低的层。
3
In many cases of regional water resources issues, when numerical method is often adopted in groundwater flow modeling lower bed level value of aquifer on each node should be given.