The files dates.cpp, dates.h, watdefs.h are from 
http://www.projectpluto.com/source.htm#date_cpp and are copyright (c) 
Project Pluto.  The author, Bill J. Gray, has given permission for them 
to be re-released under GPL-2.


The files convdates.c and convdates.R are by Thomas Lumley and are
hereby placed in the public domain.
