db/journals/jacm/BeeriBG89.html Catriel Beeri Philip A. Bernstein Nathan Goodman A model for concurrency in nested transactions systems. 230-269 1989 36 J. ACM 2 http://doi.acm.org/10.1145/62044.62046 db/journals/jacm/jacm36.html#BeeriBG89 JACM/36/P0230.pdf