Here are the sources of the various files in this directory.

VTKData is distributed under a BSD license.

John Burkardt's pages
(http://people.sc.fsu.edu/~burkardt/data/data.html) list some of the
data as LGPL and others without an explicit mention of any licensing.
Unfortnately, we are unable to find his email address anywhere.
Attempts to contact him at certain addresses results in bounced emails.

Particles.raw   - VTKData
caffeine.pdb    - VTKData
cellsnd.ascii.inp - http://people.sc.fsu.edu/~burkardt/data/data.html
clown.facet - VTKData
cow.g - VTKData
cube.vti - Self made.
edgeFaceElem.exii - VTKData
example.dem - Self made from VTKData.
foot.mha - VTKData
foot.raw - VTKData
humanoid_tri.stla - http://people.sc.fsu.edu/~burkardt/data/data.html
nut.slc - VTKData
points.txt - VTKData
prism.neu - VTKData
pyramid.ply - http://people.sc.fsu.edu/~burkardt/data/data.html
pyramid_ug.vtu - Self made.
shuttle.obj - http://people.sc.fsu.edu/~burkardt/data/data.html
tiny.q - Contributed by Francesco Poli
tiny.xyz - Contributed by Francesco Poli

