Kim B. Bruce Peter Wegner An Algebraic Model of Subtype and Inheritance. 75-96 DBPL1987/P075.pdf 1987 DBPL db/conf/dbpl/dbpl87.html#BruceW87 conf/dbpl/87 conf/lics/BruceL88 ... journals/csur/CardelliW85 conf/popl/FutatsugiGJM85 journals/tcs/GoguenM92 ... ... books/mit/shriverW87/Wegner87