Charles Ehresmann

Drawing Trees : How Many Circles to Use ?

Felix Klein, E. H. Moore, Charles Ehresmann, 2009 .

Trends toward unity in mathematics

Charles Ehresmann, 1966 .

Introduction to the theory of structured categories : Technical Report 10.(New Series) University of Kansas, Departmentof Mathematics

Charles Ehresmann, Charles Ehresmann, 1966 .

Category Theory, Homology Theory and their Applications II

Peter Hilton, F. William Lawvere, Saunders Mac Lane, 1969 .

Categories of sketched structures

Charles Ehresmann, Andrée Bastiani, Charles Ehresmann, 1972 .