At the broadest level, you can specify a root element of set when including two or more books; for example, a whole reference collection.

在最高级别上，可以在包括两个或多个books(例如整个参考资料集合)时指定根元素set。

Based on the field investigation and reference collection, the floristic analysis of pteridophyte in Niumulin Nature Reserve was studied.

在野外调查与资料查阅的基础上，对福建牛姆林自然保护区蕨类植物资源进行区系分析。

Reference objects introduce some additional costs into the garbage collection process.

引用对象给垃圾收集过程带来了一些附加的成本。

If an object is reference rich, it puts pressure on both allocation and collection.

如果一个对象引用了太多其他对象，它给分配和收集都增加了压力。

Besides garbage collection, two other approaches are commonly used to deal with the problems of aliasing: reference counting and ownership management.

除了垃圾收集之外，通常还有其他两种方法用于处理别名问题：引用计数和所有权管理。