@article {ScVe04,
AUTHOR = {Schimmerling, Ernest and Velickovic, Boban},
TITLE = {Collapsing functions},
JOURNAL = {MLQ Math. Log. Q.},
FJOURNAL = {MLQ. Mathematical Logic Quarterly},
VOLUME = {50},
YEAR = {2004},
NUMBER = {1},
PAGES = {3--8},
}