[ThePhysicist]

During my time at university, "Numerical Recipes" (https://de.wikipedia.org/wiki/Numerical_Recipes) was always the gold standard for implementations of standard / common numerical algorithmis.

Then of course there is "The Art of Computer Programming" (https://de.wikipedia.org/wiki/The_Art_of_Computer_Programmin...) which has one book dedicated to numerical algorithms as well.