.. _Astropy: http://astropy.org
.. _Matplotlib: http://www.matplotlib.org
.. _Numpy: http://www.numpy.org
.. _Python: http://www.python.org
.. _PyYAML: http://pyyaml.org/
.. _Sympy: http://docs.sympy.org/
.. _emcee: http://dan.iel.fm/emcee/current/
