Loose Diagrams, Semigroupoids, Categories, Groupoids and Iteration.

Giorgio Germano Stefano Mazzanti Loose Diagrams, Semigroupoids, Categories, Groupoids and Iteration. 64-80 1987 conf/csl/1987 CSL db/conf/csl/csl87.html#GermanoM87 http://dx.doi.org/10.1007/3-540-50241-6_30