@article{DOCMA_2014__19__a35,
     author = {Ershov, Mikhail and L\"uck, Wolfgang},
     title = {The first $L^2${-Betti} number and approximation in arbitrary characteristic},
     journal = {Documenta mathematica},
     pages = {313--331},
     publisher = {mathdoc},
     volume = {19},
     year = {2014},
     language = {en},
     url = {http://geodesic.mathdoc.fr/item/DOCMA_2014__19__a35/}
}