@article {Vel86b,
AUTHOR = {Veli{\v{c}}kovi{\'c}, Boban},
TITLE = {Jensen's {$\square$} principles and the {N}ov\'ak number of partially ordered sets},
JOURNAL = {J. Symbolic Logic},
FJOURNAL = {The Journal of Symbolic Logic},
VOLUME = {51},
YEAR = {1986},
NUMBER = {1},
PAGES = {47--58},
}