@ARTICLE{GibsonLynch89,
  author = {Gibson, {J. Paul} and Lynch, {J.A.}},
  title = {Applying Formal Object Oriented Design Principles to {Smalltalk-80}},
  journal = {British Telecom Technology Journal},
  year = {1989},
  volume = {7},
  number = {3},
  month = jul,
  pages ={12–24},
  doi = {10.1016/0950-5849(90)90026-N}
}