The Free On-line Dictionary of Computing (30 December 2018):

Yourdon methodology

    The software engineering methodology
   developed by Edward Yourdon and colleagues in the 1970s and
   1980s.  "Yourdon methodology" is a generic term for all of the
   following methodologies: Yourdon/Demarco,
   Yourdon/Constantine, Coad/Yourdon.

   (1995-04-07)