@techreport{TR-DCC-92-10,
  number = {DCC-92-10},
  author = {Kowaltowski, Tomasz},
  title = {Examples of Informal but Rigorous Correctness Proofs for Tree Traversing Algorithms},
  month = {November},
  year = {1992}, 
  institution = {Department of Computer Science, University of Campinas},
  note = {In English, 26 pages.
    \par\selectlanguage{english}\textbf{Abstract}
      Correctness of several tree traversing algorithms is proved in
      an informal but quite rigorous way by using induction and a
      convenient graphical representation for the state of
      computation.  These proofs are much simpler than their formal
      counterparts and provide an intuitive insight for the ideas
      behind the algorithms.
  }
}