@techreport {DRP-200906-Valafar,
   type = {Directed Research Project},
   author = {Masoud Valafar},
   title = {Characterizing User Interactions in Flickr Social Network},
   institution = {University of Oregon, Computer and Information Sciences Department},
   number = DRP-200906-Valafar,
   month = 6,
   year = 2009,
   note = {Available at \url{https://www.cs.uoregon.edu/Reports/DRP-200906-Valafar.pdf}},
}