@INPROCEEDINGS{HeerenLeijen:nioc,
   author  = {Bastiaan Heeren and Daan Leijen},
   title   = {Functioneel Programmeren met {Helium}},
   booktitle = {NIOC'2004},
   month   = nov,
   year    = 2004,
   pages   = {73--82}
   isbn    = {90-5452-124-4}
}