Etsuya Shibayama Akinori Yonezawa Optimistic and Pessimistic Synchronization in Distributed Computing. 257-260 1989 conf/plisp/1989 Workshop on Parallel Lisp db/conf/plisp/plisp1989.html#ShibayamaY89 http://dx.doi.org/10.1007/BFb0024159