ZE 114514

Hiya - anyone knows where the source of the following quote (as in the thread's first message) is from please? I'm doing a research proposal on sonata form, and would like to cite it and I'd need the exact source. Thank you! "having written some absolutely regular sonata-allegros, we shall state that one thing in that form has become obsolete: the recapitulation. Then we shall try once more to keep what is most essential: the development. there are two in a sonata-allegro: the middle, modulating development; the terminal development, generally built over understood dominant and tonic pedals. We shall be able to write pieces made of this terminal development alone"