Daren Nestor Luke O'Malley Aaron J. Quigley Ernst Sikora Steffen Thiel Visualisation of Variability in Software Product Line Engineering. 71-78 2007 VaMoS http://www.vamos-workshop.net/proceedings/VaMoS_2007_Proceedings.pdf conf/vamos/2007 db/conf/vamos/vamos2007.html#NestorOQST07