If you’re looking for legitimate access:
Fischer has shared several excerpts and related sequences from his Basics series that are vital for double-stop technique: simon fischer double stops pdf
is a comprehensive, 346-page pedagogical resource published by Fitzroy Music Press that redefines the traditional approach to double-stop mastery. Unlike standard scale books like Flesch, which present scales as finished products, Fischer's work is a "scale-study book" that treats the complete scale as the final stage of a detailed building process. If you’re looking for legitimate access: Fischer has
However, this last point leads us to a critical conversation. which present scales as finished products