@article{CRMATH_2005__341_9_583_0,
     author = {Roger B. Nelsen and Manuel \'Ubeda Flores},
     title = {The lattice-theoretic structure of sets of bivariate copulas and quasi-copulas},
     journal = {Comptes Rendus. Math\'ematique},
     pages = {583--586},
     publisher = {Elsevier},
     volume = {341},
     number = {9},
     year = {2005},
     doi = {10.1016/j.crma.2005.09.026},
     language = {en},
}