Giuseppa Carrà Ferro Giovanni Gallo A Procedure to Prove Statements in Differential Geometry. 203-209 1990 6 J. Autom. Reason. 2 db/journals/jar/jar6.html#FerroG90 https://doi.org/10.1007/BF00245819 https://www.wikidata.org/entity/Q115395141