Colin F. Snook Michael Poppleton Ian Johnson Rigorous engineering of product-line requirements: A case study in failure management. 112-129 2008 50 Inf. Softw. Technol. 1-2 https://doi.org/10.1016/j.infsof.2007.10.010 db/journals/infsof/infsof50.html#SnookPJ08