Distributive laws of directed containers : [extended abstract]Ahman, Danel; Uustalu, Tarmo11th International Workshop on Coalgebraic Methods in Computer Science : CMCS 2012 : Tallinn, Estonia, 31 March - 1 April 2012 : short contributions2012 / [p. 1-3] https://cs.ioc.ee/~danel/papers/cmcs12.pdf