Here are some places where you can look for information about atlasBREX: Automated template-derived brain extraction in animal MRI:

Homepage
atlasBREX: Automated template-derived brain extraction in animal MRI has a homepage that can be found at https://github.com/jlohmeier/atlasBREX
Wiki
atlasBREX: Automated template-derived brain extraction in animal MRI has a wiki that can be found here.