@unpublished{neu2004,
 author = {J. M. Siskind},
 title = {Algorithmic Differentiation of Functional Programs},
 location = {Northeastern University},
 date = 8,
 month = aug,
 year = 2004,
 url = {http://engineering.purdue.edu/~qobi/tweet-talks/neu2004-slides.pdf}}