Concurrent OO langauges, microthreads, fibers and similar stuff :)

• Possible approaches for integrating concurrency into object-oriented programming languages - Concurrent Object-Oriented Programming
  
• Lightweight Languages 2 Conference (link), including a nice "Concurrency-Oriented Programming in Erlang" section
  
• A foundation for actor computation (article)
  
• Typing concurrent objects and actors (2000) - article
  
• A Concurrent Object Calculus: Reduction and Typing (1998) - article
  
• Charming Python: Implementing "weightless threads" with Python generators (link)
  
• Microthread (wikipedia)
  
• Fiber (similar to coroutines - link)
  
• Microthread - An Object Behavioral Pattern for Managing Object
  Execution (link)
• 
  A Virtual Machine for a Process Calculus (article)