Add references to docs

doc/index.rst

@@ -11,6 +11,7 @@ Contents:
     geometry
     operators
     utils
+    references
     misc
     🚀 Github <https://github.com/inducer/grudge>
     💾 Download Releases <https://pypi.org/project/grudge>

doc/references.rst

+References
+==========
+
+..
+    When adding references here, please use the demonstrated format:
+    [FirstAuthor_pubyear]
+
+.. [Shewchuk_2002] J. R. Shewchuk (2002), \
+    What Is a Good Linear Finite Element? - \
+    Interpolation, Conditioning, Anisotropy, and Quality Measures, \
+    In Proc. of the 11th International Meshing Roundtable \
+    `(link) <http://citeseerx.ist.psu.edu/viewdoc/summary?doi=10.1.1.19.2164>`__
+
+.. [Hesthaven_2008] J. S. Hesthaven and T. Warburton (2008), \
+    Nodal Discontinuous Galerkin Methods: Algorithms, Analysis, and Applications, \
+    Springer \
+    `(doi) <https://doi.org/10.1007/978-0-387-72067-8>`__