Add bifurcation and simualtion references

Author: TorkelE

docs/src/catalyst_applications/advanced_simulations.md

@@ -401,3 +401,8 @@ species we wish to plot. Here, we plot the solution in `(X,Y)` space:
 ```@example ex4
 plot(sol; idxs=(:X, :Y))
 ```
+
+---
+## References
+[^1]: [DifferentialEquations.jl online documentation.](https://docs.sciml.ai/DiffEqDocs/stable/)
+[^2]: [Chris Rackauckas, Qing Nie, *DifferentialEquations.jl – A Performant and Feature-Rich Ecosystem for Solving Differential Equations in Julia*, Journal of Open Resource Software (2017).](https://openresearchsoftware.metajnl.com/articles/10.5334/jors.151)

docs/src/catalyst_applications/bifurcation_diagrams.md

@@ -110,3 +110,7 @@ branches are connected. However, BifurcationKit.jl is a very powerful package
 capable of a lot more. For more details, please see that package's
 documentation:
 [BifurcationKit.jl](https://bifurcationkit.github.io/BifurcationKitDocs.jl/stable/).
+
+---
+## References
+[^1]: [Yuri A. Kuznetsov, *Elements of Applied Bifurcation Theory*, Springer (2023).](https://link.springer.com/book/10.1007/978-3-031-22007-4)