@inproceedings{popl2007a,
 author = {B. A. Pearlmutter and
           J. M. Siskind},
 title = {Lazy Multivariate Higher-Order Forward-Mode {AD}},
 booktitle = {Proceedings of the Annual Symposium on Principles of
              Programming Languages (POPL)},
 pages = {155-160},
 location = {Nice, France},
 day = {17--19},
 month = jan,
 year = 2007,
 url = {http://engineering.purdue.edu/~qobi/papers/popl2007a.pdf}}