@article{SOVS11,
  author = {B. \v{S}kori\'{c} and C. Obi and E. Verbitskiy and B. Schoenmakers},
  title = {Sharp lower bounds on the extractable randomness from non-uniform sources},
  journal = {Information and Computation},
  volume = {209},
  year = {2011},
  pages = {1184--1196},
  doi = {10.1016/j.ic.2011.06.001}
}