@article{10_4153_CJM_2011_098_9,
     author = {Aguiar, Marcelo and Lauve, Aaron},
     title = {Lagrange's {Theorem} for {Hopf} {Monoids} in {Species}},
     journal = {Canadian journal of mathematics},
     pages = {241--265},
     year = {2013},
     volume = {65},
     number = {2},
     doi = {10.4153/CJM-2011-098-9},
     url = {http://geodesic.mathdoc.fr/articles/10.4153/CJM-2011-098-9/}
}