@INPROCEEDINGS{Leijen:hdirect,
author      = {Sigbj\"orn Finne and Daan Leijen and Erik Meijer and Peyton Jones, Simon},
title       = {Calling Hell from Heaven and Heaven from Hell},
booktitle   = {The International Conference on Functional Programming (ICFP'99)},
address     = {{P}aris, {France}},
year        = {1999},
note        = {Also appeared in {ACM SIGPLAN} {N}otices 34, 9, (Sep. 1999)}
}