(32) http://grin.hq.nasa.gov/ABSTRACTS/GPN-2000-001315.html. Public Domain.
(33) http://commons.wikimedia.org/wiki/Image:Light-wave.svg. GNU-FDL.
(34) http://commons.wikimedia.org/wiki/Image:Meadelx200_kl.jpg. Public Domain.
(35) John Lanoue.http://en.wikipedia.org/wiki/Image:M31_Lanoue.png. Public
Domain.
