@article{BoSc09,
    author      = {Bostan, Alin and Schost, {\'E}ric},
    title       = {A simple and fast algorithm for computing exponentials of
  power series},
    journal     = {Information Processing Letters},
    number      = {13},
    year        = {2009},
    volume      = {109},
    pages       = {754--756},
    doi         = {10.1016/j.ipl.2009.03.012},
    abstract    = {As was initially shown by Brent, exponentials of truncated
  power series can be computed using a constant number of polynomial
  multiplications. This note gives a relatively simple algorithm with a low
  constant factor.},
}