@article{JOLT_2007_17_2_a1,
     author = {Martin Markl},
     title = {Lie {Elements} in {Pre-Lie} {Algebras,} {Trees} and {Cohomology} {Operations}},
     journal = {Journal of Lie Theory},
     pages = {241--261},
     year = {2007},
     volume = {17},
     number = {2},
     url = {http://geodesic.mathdoc.fr/item/JOLT_2007_17_2_a1/}
}