@InProceedings{Cook87a,
  author =       "Steve Cook",
  title =        "Varieties of Inheritance",
  booktitle =    "OOPSLA '87 Addendum To The Proceedings",
}

@misc{ scharli-traits,
  author = "N. Sch{\"a}rli and S. Ducasse and O. Nierstrasz and A. Black",
  title = "Traits: Composable Units of Behavior",
}

@article{statefull,
 author = {A. Bergel and S. Ducasse and O. Nierstrasz and R. Wuyts},
 title = {Stateful traits and their formalization},
 journal = {Comput. Lang. Syst. Struct.},
 volume = 34,
 number = {2-3},
 year = 2008,
 issn = {1477-8424},
 pages = {83--108},
 }

@inproceedings{freezable,
 author = {S. Ducasse and R. Wuyts and A. Bergel and O. Nierstrasz},
 title = {User-changeable visibility: resolving unanticipated...},
 booktitle = {OOPSLA '07},
 year = {2007},
 pages = {171--190},
 location = {Montreal, Quebec, Canada},
 }