@article {ToVe87,
AUTHOR = {Todor{\v{c}}evi{\'c}, S. and Veli{\v{c}}kovi{\'c}, B.},
TITLE = {Martin's axiom and partitions},
JOURNAL = {Compositio Math.},
FJOURNAL = {Compositio Mathematica},
VOLUME = {63},
YEAR = {1987},
NUMBER = {3},
PAGES = {391--408},
}