@techreport {TR-1980-012,
   type = {Technical Report},
   author = {Sandra Hedetniemi, Stephen Hedetniemi, Terry Beyer},
   title = {A Linear Algorithm for Finding the Center of a Unicyclic Graph},
   institution = {University of Oregon, Computer and Information Sciences Department},
   number = TR-1980-012,
   year = 1980,
   note = {Available at \url{https://www.cs.uoregon.edu/Reports/TR-1980-012.pdf}},
}