@article{JEMS_2012_14_5_a10,
     author = {Mikl\'os Ab\'ert and Nikolay Nikolov},
     title = {Rank gradient, cost of groups and the rank versus {Heegaard} genus problem},
     journal = {Journal of the European Mathematical Society},
     pages = {1657--1677},
     publisher = {mathdoc},
     volume = {14},
     number = {5},
     year = {2012},
     doi = {10.4171/jems/344},
     url = {http://geodesic.mathdoc.fr/articles/10.4171/jems/344/}
}