Fix broken link

README.rst

@@ -264,4 +264,4 @@ A recent survey on various regression models including GMR is the following:
 
     [3] F. Stulp, O. Sigaud, "Many regression algorithms, one unified model: A review," in Neural Networks, vol. 69, 2015, pp. 60-79, doi: `10.1016/j.neunet.2015.05.005 <https://doi.org/10.1016/j.neunet.2015.05.005>`_.
 
-Sylvain Calinon has a good introduction in his `slides on nonlinear regression <http://calinon.ch/misc/EE613/EE613-slides-9.pdf>`_ for his `machine learning course <http://calinon.ch/teaching_EPFL.htm>`_.
+Sylvain Calinon has a good introduction in his `slides on nonlinear regression <https://calinon.ch/misc/EE613/EE613-nonlinearRegression.pdf>`_ for his `machine learning course <http://calinon.ch/teaching_EPFL.htm>`_.