@article{ASCFM_1976__60_13_31_0,
     author = {Aiello, Luigia and Aiello, Mario and Attardi, Giuseppe and Prini, Gianfranco},
     title = {Informal proofs formally checked by machine},
     journal = {Annales scientifiques de l'Universit\'e de Clermont. Math\'ematiques},
     pages = {31--53},
     publisher = {UER de Sciences exactes et naturelles de l'Universit\'e de Clermont},
     volume = {60},
     number = {13},
     year = {1976},
     mrnumber = {468369},
     zbl = {0352.68110},
     language = {en},
     url = {http://www.numdam.org/item/ASCFM_1976__60_13_31_0/}
}