Compositions of maps and hypermaps. (Compositions des cartes et hypercartes.) El Marraki, Mohamed; Zvonkin, Alexander — 1995 Séminaire Lotharingien de Combinatoire [electronic only]
Cacti, braids and complex polynomials. El Marraki, Mohamed; Hanusse, Nicolas; Zipperer, Jörg; Zvonkin, Alexander — 1996 Séminaire Lotharingien de Combinatoire [electronic only]