@InProceedings{FilLet2004, author = {J.-C. Filli{\^a}tre and P. Letouzey}, title = {{Functors for Proofs and Programs}}, booktitle = {{European Symposium on Programing, ESOP'2004}}, editor = {D. Schmidt}, volume = 2986, publisher = {Springer-Verlag}, series = {Lecture Notes in Computer Science}, year = 2004 }