@article{10_4171_dm_644,
     author = {Matthieu Romagny and David Rydh and Gabriel Zalamansky},
     title = {The {Complexity} of a {Flat} {Groupoid}},
     journal = {Documenta mathematica},
     pages = {1157--1196},
     year = {2018},
     volume = {23},
     doi = {10.4171/dm/644},
     url = {http://geodesic.mathdoc.fr/articles/10.4171/dm/644/}
}