Fixed references

references/annexes.bib

@@ -287,7 +287,7 @@
 }
 @online{wikipedia_complex_number,
    title = {Complex number},
-   url   = {https://en.wikipedia.org/wiki/Complex_number}
+   url   = {https://en.wikipedia.org/wiki/Complex\_number}
 }
 @online{wikipedia_quaternion,
    title = {Quaternion},
@@ -301,3 +301,35 @@
    title = {Sedenion},
    url   = {https://en.wikipedia.org/wiki/Sedenion}
 }
+@online{wikipedia_function_mathematics,
+  title = {Function (mathematics)},
+  url   = {https://en.wikipedia.org/wiki/Function\_(mathematics)}
+}
+@online{wikipedia_domain_function,
+  title = {Domain of a function},
+  url   = {https://en.wikipedia.org/wiki/Domain\_of\_a\_function}
+}
+@online{wikipedia_codomain,
+  title = {Codomain},
+  url   = {https://en.wikipedia.org/wiki/Codomain}
+}
+@online{wikipedia_set_theory,
+  title = {Set theory},
+  url   = {https://en.wikipedia.org/wiki/Set\_theory}
+}
+@online{wikipedia_injective_function,
+  title = {Injective function},
+  url   = {https://en.wikipedia.org/wiki/Injective\_function}
+}
+@online{wikipedia_surjective_function,
+  title = {Surjective function},
+  url   = {https://en.wikipedia.org/wiki/Surjective\_function}
+}
+@online{wikipedia_bijection,
+  title = {Bijection},
+  url   = {https://en.wikipedia.org/wiki/Bijection}
+}
+@online{wikipedia_hyperbolic_functions,
+  title = {Hyperbolic functions},
+  url   = {https://en.wikipedia.org/wiki/Hyperbolic\_functions}
+}