@TechReport{Dartmouth:TR2004-528,
  author = {Hany Farid},
  title = {{Discrete-Time Fractional Differentiation from Integer Derivatives }},
  institution = {Dartmouth College, Computer Science},
  address = {Hanover, NH},
  number = {TR2004-528},
  year = {2004},
  month = {December},
  URL = {http://www.cs.dartmouth.edu/reports/TR2004-528.pdf},
  abstract = {
    Discrete-time fractional derivative filters (1-D and 2-D) are shown to
    be well approximated from a small set of integer derivatives. A
    fractional derivative of arbitrary order (and, in 2-D, of arbitrary
    orientation) can therefore be efficiently computed from a linear
    combination of integer derivatives of the underlying signal or image.
  }
}