MJCollins> This can also be found in chapter 7.5 of Graham/Knuth/Patashnik "Concrete Mathematics". WD> Which I find available online at https://notendur.hi.is/pgg/(ebook-pdf)%20-%20Mathematics%20-%20Concrete%20Ma... <https://notendur.hi.is/pgg/%28ebook-pdf%29%20-%20Mathematics%20-%20Concrete%20Mathematics.pdf> Whit This pdf is a case of getting what you pay for. Yes, it will probably teach you Raney's lemma, but it is an OCR of a book that someone has scribbled in, and is full of dangerous errors (e.g., missing minus signs) and hopeless garbles. In citing their reasons for creating the controversial Euler font for this book, GK&P cagily forgot to mention confounding piracy! However much you may dislike the Euler font, it is bliss compared to the insanely random caca from the OCRware trying to imitate it. --rwg The only thing nearly as ugly was the preview copy of his latest edition Addison Wesley sent DEK after punting their fine old printer and switching to phototypesetting. It was laughable. I wonder if anyone (in the Free World) would have paid money for it. It was why he had to drop everything and build TeX and MetaFont.