@article{10_1017_S0017089504001934,
     author = {GREEN, R. M.},
     title = {ACYCLIC {HEAPS} {OF} {PIECES,} {II}},
     journal = {Glasgow mathematical journal},
     pages = {459--476},
     year = {2004},
     volume = {46},
     number = {3},
     doi = {10.1017/S0017089504001934},
     url = {http://geodesic.mathdoc.fr/articles/10.1017/S0017089504001934/}
}