Question: What data sources do they use for creating their dataset?
Answer: Wikipedia (of 250-600 characters) from the manually curated HotpotQA training set, Manually Annotated Sub-Corpus (MASC) of the Open American National Corpus), RTE5
Alternative answer: Wikipedia (of 250-600 characters) from the manually curated HotpotQA training set, formal spoken text (excerpted from court and presidential debate transcripts in the Manually Annotated Sub-Corpus (MASC) of the Open American National Corpus), causal or procedural text, which describes sequences of events or actions, extracted from WikiHow, annotations using the longer contexts present in the GLUE RTE training data, which came from the RTE5 dataset