@article{2019-gogolla-jot-j,
  author    = {Martin Gogolla and
               Antonio Vallecillo},
  title     = {On Softening {OCL} Invariants},
  journal   = {Journal of Object Technology},
  volume    = {18},
  number    = {2},
  pages     = {6:1--22},
  year      = {2019},
  month     = jul,
  doi       = {10.5381/jot.2019.18.2.a6},
  issn      = {1660-1769},
}