Add refs for all tables

[SoongNoonien]

These are just the references for the character tables. The Greenfunction tables are still missing.

[codecov]

Codecov Report

All modified and coverable lines are covered by tests ✅

Project coverage is 95.99%. Comparing base (22c6dde) to head (a68fb48).
Report is 4 commits behind head on master.

Additional details and impacted files

@@            Coverage Diff             @@
##           master     #217      +/-   ##
==========================================
+ Coverage   95.80%   95.99%   +0.19%     
==========================================
  Files          13       13              
  Lines         786      849      +63     
==========================================
+ Hits          753      815      +62     
- Misses         33       34       +1     

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[fingolfin]

Could at least link to https://publications.rwth-aachen.de/record/821447

And then we could have a note or so which says "See also ..." and points to https://link.springer.com/chapter/10.1007/978-3-0348-8658-1_17 (and we should add that to the bib, too -- at the bottom of the page there is citation info, or perhaps zbmath or mathscinet has it, too)

[SoongNoonien]

And then we could have a note or so which says "See also ..." and points to https://link.springer.com/chapter/10.1007/978-3-0348-8658-1_17 (and we should add that to the bib, too -- at the bottom of the page there is citation info, or perhaps zbmath or mathscinet has it, too)

I'm sorry, I don't get it. Where could we add a note about what? Something like:

Suggested change

	zbmath = {51240}
	zbmath = {51240},
	note = {See also: https://link.springer.com/chapter/10.1007/978-3-0348-8658-1_17}