Reference. Open diagrams via coend calculus [garner-lopez-franco-2016-commutativity]

@article{roman-2021-open,
   title={Open Diagrams via Coend Calculus},
   volume={333},
   ISSN={2075-2180},
   url={http://dx.doi.org/10.4204/EPTCS.333.5},
   DOI={10.4204/eptcs.333.5},
   journal={Electronic Proceedings in Theoretical Computer Science},
   publisher={Open Publishing Association},
   author={Román, Mario},
   year={2021},
   month=feb, pages={65–78}
   }