Yiqiao XuCollin F. LynchTiffany BarnesHow many friends can you make in a week?: evolving social relationships in MOOCs over time.2018EDMhttp://educationaldatamining.org/files/conferences/EDM2018/papers/EDM2018_paper_64.pdfconf/edm/2018db/conf/edm/edm2018.html#XuLB18