Task: Question Answering
Input (English): In BIBREF8 a refined collection of tweets gathered from twitter is presented. Their dataset which is labeled for named entity recognition task contains 8,257 tweets. There are 12,784 entities in total in this dataset. Table TABREF19 shows statistics related to each named entity in training, development and test sets.

 
 Question: What datasets did they use?
Output (English): BIBREF8 a refined collection of tweets gathered from twitter