PLUMED2 is covered under the GNU LESSER GENERAL PUBLIC LICENSE (see ./COPYING.LESSER).
This license applies to all the source code in this tree, except from where
explicitly indicated.

Authors of this software are:

Massimiliano Bonomi
Davide Branduardi
Giovanni Bussi
Carlo Camilloni
Gareth Tribello

Notice that some of the PLUMED modules are released under different
licenses. In each module with this exception, you should find a file
named COPYRIGHT stating the exact licence. Look for files
in the form src/*/COPYRIGHT

