Weber, Mark Max Planck Institute for Mathematics, Max Planck Society;
https://www.emis.de/journals/TAC/volumes/28/2/28-02.pdf (Publisher version)
Weber_Free products of higher operad algebras_2012.pdf (Publisher version), 471KB
Weber, M. (2013). Free products of higher operad algebras. Theory and Applications of Categories, 28(2), 24-65.