@InProceedings{stone+:singletons, author = {Christopher A. Stone and Robert Harper}, title = {Deciding Type Equivalence in a Language with Singleton Kinds}, booktitle = twentyseventh # popl, pages = {214--227}, year = 2000, address = {Boston}, month = {January} } @Article{stone+:singletons-tocl, author = {Christopher A. Stone and Robert Harper}, title = {Extensional Equivalence and Singleton Types}, journal = {{ACM} Transactions on Computational Logic}, year = {2005?}, number = {??}, pages = {??--??}, month = {??}, note = {(To appear.)} }