call subroutine in dll A from subroutine in dll B

I have some LAPACK routines (F95 or F77?) in a DLL and write some stubs to cal the LAPACK routines that I call  from C#
I put those stubs in another DLL.
At least, that's the general idea to solve the problem of having to recompile ALL the Fortran many times, when I put everything in one DLL.
I want to build the LAPACK dll only once and develop the stubs separately.
How would I do this calling of the LAPACK routines?

I was pointed to "modules" and to "loadlibrary" which seem to be quite different approaches.

I use VS2015 on win10 and call from c#, which goes well.