@article{10_4064_cm131_1_11,
     author = {Timothy A. Schroeder},
     title = {$\ell ^{2}$-homology and planar graphs},
     journal = {Colloquium Mathematicum},
     pages = {129--139},
     publisher = {mathdoc},
     volume = {131},
     number = {1},
     year = {2013},
     doi = {10.4064/cm131-1-11},
     language = {en},
     url = {http://geodesic.mathdoc.fr/articles/10.4064/cm131-1-11/}
}