@article{RSMUP_1993__90__67_0,
     author = {Hill, Paul and Megibben, Charles},
     title = {Butler groups cannot be classified by certain invariants},
     journal = {Rendiconti del Seminario Matematico della Universit\`a di Padova},
     pages = {67--79},
     publisher = {Seminario Matematico of the University of Padua},
     volume = {90},
     year = {1993},
     mrnumber = {1257133},
     zbl = {0808.20044},
     language = {en},
     url = {http://archive.numdam.org/item/RSMUP_1993__90__67_0/}
}