BIBCYT http://bibcyt.ucla.edu.ve/cgi-win/be_alex.exe?Ultimo&Nombrebd=BIBCYT UCLA - Biblioteca de Ciencias y Tecnologia Felix Morales Bueno Helferich, Andreas P Principal Schmid, Klaus P Principal Herzwurm, Georg P Principal Product Management for Software Product Lines: An unsolved problem? Vol: 49 pp. 66-67