Many people have contributed to lmfit.

Matthew Newville wrote the original implementation.
Till Stensitzki wrote the improved estimates of confidence intervals, 
     and contributed many tests, bug fixes, and documentation.
Daniel B. Allan wrote much of the high level Models, and many 
     improvements to the testing and documentation.
J. J. Helmus wrote the MINUT bounds for leastsq, originally in
     leastsqbounds.py, and ported to lmfit.
E. O. Lebigot wrote the uncertainties package, a version of which is 
     used here. 

Additional patches, bug fixes, and suggestions have come from 
  Christohp Deil, Francois Boulogne, Colin Brosseau, nmearl, 
  Gustavo Pasquevich, and Ben Gamari
