@ARTICLE{VO3,
  author = {Vorel, Vojt\v{e}ch and Roman, Adam},
  title = {Parameterized Complexity of Synchronization and Road Coloring},
  journal = {Discrete Mathematics {\&} Theoretical Computer Science},
  year = {2015},
  volume = {17},
  pages = {307-330},
  number = {1}
}