@article{RSMUP_1989__82__133_0,
     author = {Held, D. and Hrab\v{e} de Angelis, J.},
     title = {A block-theory-free characterization of $M_{24}$},
     journal = {Rendiconti del Seminario Matematico della Universit\`a di Padova},
     pages = {133--150},
     publisher = {Seminario Matematico of the University of Padua},
     volume = {82},
     year = {1989},
     mrnumber = {1049588},
     zbl = {0705.20013},
     language = {en},
     url = {http://archive.numdam.org/item/RSMUP_1989__82__133_0/}
}