Python 的虛擬環境及多版本開發利器─Virtualenv 與 Pythonbrew
http://www.openfoundry.org/tw/tech-column/8516-pythons-virtual-environment-and-multi-version-programming-tools-virtualenv-and-pythonbrew
How to install and manage different versions of Python in Linux
http://www.howopensource.com/2011/05/how-to-install-and-manage-different-versions-of-python-in-linux/
python: what's the difference between pythonbrew and virtualenv?
http://stackoverflow.com/questions/8256723/python-whats-the-difference-between-pythonbrew-and-virtualenv