Andreas Gawecki Florian Matthes Integrating Subtyping, Matching and Type Quantification: A Practical Perspective. 26-47 http://link.springer.de/link/service/series/0558/bibs/1098/10980026.htm 1996 conf/ecoop/1996 ECOOP db/conf/ecoop/ecoop96.html#GaweckiM96