Programming with a Differentiable Forth Interpreter, Bosnjak, Matko, Rocktaschel, Tim, Naradowsky, Jason and Riedel, Sebastian, arXiv preprint arXiv:1605.06640 2016 [pdf] 
@article{bosnjak2016programming,
    journal={arXiv preprint arXiv:1605.06640}, 
    month={May}, 
    year={2016}, 
    author={Bosnjak, Matko and Rocktaschel, Tim and Naradowsky, Jason and Riedel, Sebastian}, 
    title={Programming with a Differentiable Forth Interpreter}, 
}