Andrew Ng Tutorial: https://web.stanford.edu/class/cs294a/sparseAutoencoder_2011new.pdf
UFLDL Exercise: http://ufldl.stanford.edu/wiki/index.php/Exercise:Sparse_Autoencoder
A Chinese blog: http://www.cnblogs.com/tornadomeet/archive/2013/03/20/2970724.html
Stacked Denoising Autoencoder (paper): http://jmlr.csail.mit.edu/papers/volume11/vincent10a/vincent10a.pdf