@article{markov:1981:oti,
    author = {Markov, S. M.},
     title = {On the interval computation of elementary functions},
   journal = {C. R. Acad. Bulgare Sci.},
  fjournal = {Doklady Bolgarsko\u\i\ Akademii Nauk. Comptes Rendus de
              l'Acad\'emie Bulgare des Sciences},
    volume = {34},
      year = {1981},
    number = {3},
     pages = {319–322},
      issn = {0366-8681},
     coden = {CRABAA},
   mrclass = {65G10},
  mrnumber = {MR0621039 (83e:65084)},
mrreviewer = {David F. Griffiths},
     zblno = {0481.65014}}