Martin Erwig, Margaret M. Burnett. Adding Apples and Oranges. In Shriram Krishnamurthi, C. R. Ramakrishnan, editors, Practical Aspects of Declarative Languages, 4th International Symposium, PADL 2002, Portland, OR, USA, January 19-20, 2002, Proceedings. Volume 2257 of Lecture Notes in Computer Science, pages 173-191, Springer, 2002. [doi]