Jari Oksanen, F. Guillaume Blanchet, Michael Friendly, Roeland Kindt,
   Pierre Legendre, Dan McGlinn, Peter R. Minchin, R. B. O'Hara,
   Gavin L. Simpson, Peter Solymos, M. Henry H. Stevens, Eduard Szoecs,
   Helene Wagner
Ordination methods, diversity analysis and other
  functions for community and vegetation ecologists.