H. Forssell. (2011)cite arxiv:1109.0699Comment: 32 pages. This is the first pre-print version, the final revised version can be found at http://onlinelibrary.wiley.com/doi/10.1002/malq.201100080/abstract (posting of which is not allowed by Wiley). Changes in v2: updated comments.
C. Freeman, and J. Bruna. (2016)cite arxiv:1611.01540Comment: 22 Pages (10 main + Appendices), 4 Figures, 1 Table, Published as a conference paper at ICLR 2017.