@techreport {TR-1989-011,
   type = {Technical Report},
   author = {Stefan Arnborg, Andrzej Proskurowski },
   title = {Canonical Representations of Partial 2- and 3-trees },
   institution = {University of Oregon, Computer and Information Sciences Department},
   number = TR-1989-011,
   month = 7,
   year = 1989,
   note = {Available at \url{https://www.cs.uoregon.edu/Reports/TR-1989-011.pdf}},
}