Sorry I have not answered your question about where the formula came from, I got busy, then I forgot. As Gerald C Koch said, it's the Kodak formula. Available all over the place. I have it in several books, in particular, the Darkroom Cookbook, by Stephen G. Anchell. I don't use D-76, but I developed 800 sheets of 4 x 5 for a photographer, as he shipped it to me over the summer of 2010. He wanted D-76 replenished. I followed Kodak's recommended rates and the guy was pleased with the results. I used store bought developer, but mixed my own replenisher according to the formula above. If you search around you may find teaspoon equivalents if you don't have a scale.