@article{toplas2008,
 author = {B. A. Pearlmutter and
           J. M. Siskind},
 title = {Reverse-Mode {AD} in a Functional Framework: Lambda the Ultimate
          Backpropagator},
 journal = {ACM Transactions on Programming Languages and Systems (TOPLAS)},
 volume = 30,
 number = 2,
 pages = {1-36},
 month = mar,
 year = 2008,
 url = {http://engineering.purdue.edu/~qobi/papers/toplas2008.pdf}}