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Fortran 
Fortran 90 for the Fortran 77 Programmer Professional Programmer's Guide to Fortran77
Modular Programming with Fortran 90 Fortran 90 Tutorial [Another]
User Notes on FORTRAN Programming Interactive Fortran 77 (PDF)
Fortran 77 Standard Fortran 77 Tutorial [Mirror] [Mirror] [Mirror]
Numerical Recipes in Fortran 77 [Mirror] Numerical Recipes in Fortran 90 [Mirror]
Using C and C++ with Fortran