@article{10_37236_5533,
     author = {Alexander Lazar},
     title = {A chip-firing game on the product of two graphs and the tropical {Picard} group},
     journal = {The electronic journal of combinatorics},
     year = {2017},
     volume = {24},
     number = {4},
     doi = {10.37236/5533},
     zbl = {1373.05224},
     url = {http://geodesic.mathdoc.fr/articles/10.37236/5533/}
}