Eladio Domínguez Angel R. Francés An Axiomatic Approach to Digital Topology. 3-16 2000 conf/dagstuhl/2000dig Digital and Image Geometry http://link.springer.de/link/service/series/0558/bibs/2243/22430003.htm db/conf/dagstuhl/dig2000.html#DominguezF00