The solution to my question was provided by @David third link
To reference an external lib project without copy, just do this: - Insert this 2 lines on setting.gradle:
include ':your-lib-name'
project(':your-lib-name').projectDir = new File('/path-to-your-lib/your-lib-name)
Insert this line on on dependencies part of build.gradle file:
compile project(':your-lib-name')
In addition, I found my own solution
After I add the class by importing module, I right click on the module >> refactor >> Copy Class >> Then I point it to the original directory (it will ask to overwrite existing)