BibTex format
@article{Piróg:2016:10.1145/3022670.2951947,
author = {Piróg, M and Wu, N},
doi = {10.1145/3022670.2951947},
journal = {ACM SIGPLAN Notices},
pages = {490--501},
title = {String diagrams for free monads (functional pearl)},
url = {http://dx.doi.org/10.1145/3022670.2951947},
volume = {51},
year = {2016}
}