McDonnell, T. et al. 2016. Why Is That Relevant? Collecting Annotator Rationales for Relevance Judgments. Proceedings of the AAAI Conference on Human Computation and Crowdsourcing. 4, 1 (Sep. 2016), 139–148. DOI:https://doi.org/10.1609/hcomp.v4i1.13287.