Russ Atkinson and Carl Hewitt developed techniques for proving properties of Serializers that are guardians of shared resources.
Garbage collection (the automatic reclamation of unused storage) was an important theme in the development of the Actor model.
Henry Lieberman and Carl Hewitt [1983] developed a real time garbage collection based on the lifetimes of Actors (Objects).
William Athas and Nanette Boden [1988] developed Cantor which is an Actor programming language for scientific computing.
This gave rise to the so-called inheritance anomaly controversy in object-oriented concurrent programming languages [Satoshi Matsuoka and Aki Yonezawa 1993, Giuseppe Milicia and Vladimiro Sassone 2004].