chore: sync references.bib with mathlib3 (#6193)

Author: Ruben-VandeVelde

docs/references.bib

@@ -1338,6 +1338,18 @@ @Article{         huneke2002
   url           = {https://doi.org/10.1080/00029890.2002.11919853}
 }
 
+@InProceedings{   hyman1973,
+  author        = "Bass, Hyman",
+  editor        = "Bass, Hyman",
+  title         = "Unitary algebraic K-theory",
+  booktitle     = "Hermitian K-Theory and Geometric Applications",
+  year          = "1973",
+  publisher     = "Springer Berlin Heidelberg",
+  address       = "Berlin, Heidelberg",
+  pages         = "57--265",
+  isbn          = "978-3-540-37773-3"
+}
+
 @Book{            iordanescu2003,
   author        = {Radu {Iord\u{a}nescu}},
   title         = {{Jordan structures in geometry and physics. With an