@article{JLT_2004_14_2_JLT_2004_14_2_a2,
     author = {Y. Yoshii},
     title = {Root {Systems} {Extended} by an {Abelian} {Group} and their {Lie} {Algebras}},
     journal = {Journal of Lie theory},
     pages = {371--394},
     publisher = {mathdoc},
     volume = {14},
     number = {2},
     year = {2004},
     url = {http://geodesic.mathdoc.fr/item/JLT_2004_14_2_JLT_2004_14_2_a2/}
}