Android.Libraries
1. Android Dependencies, Referenced Libraries, Android Private Libraries
Android Private Libraries - Android libraries allows one to store source code and resources which are used by several other Android projects. The Android Development Tools(ADT) compile the content of library into the Android project by creating a JAR file. Using libraries, help you to structure your application code. Also more and more important Open Source libraries are available for Android. Understanding library projects is therefore important for every Android programmer.
Referenced Libraries - Referenced Libraries include all the necessary external JAR libraries that the project requires to function.
Android Dependencies - Android Dependencies is a virtual folder where Eclipse shows what JAR files the project depends on. It's not a physical folder; you won't find it on your hard disk. Deleting this folder would destroy your project.
http://stackoverflow.com/questions/20995000/what-is-the-purpose-of-the-android-private-libraries-referenced-libraries-and-a
关于这三者的官方文档在哪里?