@unpublished{Gibbons99:Lecture,
  title = "Lecture Notes on Algebraic and Coalgebraic Methods for Calculating Functional Programs",
  author = "Jeremy Gibbons",
  year = "1999",
  annote = "Functional programs are merely equations; they may be calculated by straightforward equational reasoning. Many useful theorems
for such reasoning derive from an \emph{algebraic} view of programs, built around datatypes and their operations. Traditional
algebraic methods concentrate on initial algebras, constructors, and values; dual, co-algebraic, methods concentrate on final
co-algebras, destructors, and processes. Both methods are elegant and powerful; they deserve to be combined.",
  month = "mar",
  note = "Estonian Winter School on Computer Science",
}