@article {IOPORT.50189325,
    author       = {Mazza, Christian},
    title        = {Simply generated trees, B-series and Wigner processes},
    year         = {2004},
    journal      = {Random Struct. Algorithms},
    volume       = {25},
    number       = {3},
    pages        = {293-310},
    doi          = {10.1002/rsa.20024},
    identifier   = {50189325},
}