A short paper has been published on Mosquitto in The Journal of Open Source Software If you use Mosquitto in your academic work, please now use this paper as your citation.
R. A. Light, "Mosquitto: server and client implementation of the MQTT protocol," The Journal of Open Source Software, vol. 2, no. 13, May 2017, DOI: 10.21105/joss.00265
The paper link is http://dx.doi.org/10.21105/joss.00265
A [bibtex] entry is available.