@article{CMH_1979__54_139780,
     author = {Dennis Sullivan},
     title = {A homological characterization of foliations consisting of minimal surfaces.},
     journal = {Commentarii mathematici Helvetici},
     pages = {218--223},
     publisher = {mathdoc},
     volume = {54},
     year = {1979},
     zbl = {0409.57025},
     url = {http://geodesic.mathdoc.fr/item/CMH_1979__54_139780/}
}