@article{TAC_2007_18_a12,
     author = {Kurusch Ebrahimi-Fard and Li Guo},
     title = {Coherent unit actions on regular operads and {Hopf} algebras},
     journal = {Theory and applications of categories},
     pages = {348--371},
     year = {2007},
     volume = {18},
     language = {en},
     url = {http://geodesic.mathdoc.fr/item/TAC_2007_18_a12/}
}