@unpublished{sod2007,
 author = {J. M. Siskind},
 title = {Algorithmic Differentiation of Functional Programs},
 location = {NSF Science of Design (SoD) Program PI Meeting},
 date = 28,
 month = feb,
 year = 2007,
 url = {http://engineering.purdue.edu/~qobi/tweet-talks/sod2007-slides.pdf}}