Copyright notice added to remaining files

After doing a systematic search for files without a copyright notice, a few
more were found that didn't have a notice. So a notice was added for them.

I used this Bash command to find the files:

for f in $(find ./ -type f); do \
  if [[ $f != *.git* ]]; then \
    n=$(grep -i copyright $f | wc -l); \
    echo "$n $f"; \
  fi; \
done | awk '$1==0'

1 files changed, 21 insertions, 0 deletions

diff --git a/tex/src/references.tex b/tex/src/references.tex
index 785ab21..c1c4084 100644
--- a/tex/src/references.tex
+++ b/tex/src/references.tex
@@ -1,3 +1,24 @@
+%% References used in the template paper.
+%
+%% Original author:
+%%     Mohammad Akhlaghi <mohammad@akhlaghi.org>
+%% Contributing author(s):
+%%     Your name <your@email.address>
+%% Copyright (C) 2018-2019, Your Name.
+%
+%% This template is free software: you can redistribute it and/or modify it
+%% under the terms of the GNU General Public License as published by the
+%% Free Software Foundation, either version 3 of the License, or (at your
+%% option) any later version.
+%
+%% This template is distributed in the hope that it will be useful, but
+%% WITHOUT ANY WARRANTY; without even the implied warranty of
+%% MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
+%% General Public License for more details.
+%
+%% You should have received a copy of the GNU General Public License along
+%% with Template.  If not, see <https://www.gnu.org/licenses/>.
+
 @ARTICLE{astropy2018,
    author = {{Astropy Collaboration} and {Price-Whelan}, A.~M. and {Sip{\H o}cz}, B.~M. and
 	{G{\"u}nther}, H.~M. and {Lim}, P.~L. and {Crawford}, S.~M. and