@article{Rud:75a,
  journal = {Discrete Math.},
  volume = {13},
  title = {Local properties of {B}oolean functions. {I}. {I}njectivity},
  year = {1975},
  fjournal = {Discrete Mathematics},
  pages = {143--160},
  number = {2},
  author = {Rudeanu, Sergiu},
}