@article{Barmpalias2017DifferencesHaltingProbabilities,
  title   = {Differences of halting probabilities},
  journal = {J. Comput. Syst. Sci.},
  year    = {2017},
  volume  = {89},
  pages   = {349-360},
  author  = {G. Barmpalias and A. Lewis-Pye},
}