Future
Academic Press owns the rights to G&R. We expect AP will re-do their electronic version so that it can be computer-processed in a semantically meaningful way. This should be linked to a web site with algorithms for lookup and computation. (D. Zwillinger, AzTech Inc.)
They may re-enter everything by hand (again) in a suitable “semantic” system, or perhaps use our program for a first run-through.
It is not clear how many more large-scale TeX-based references or journals may be worth attempting, but our experience suggests that, with some effort, additional programming could bring this or similar material up to a 80% or more recognition rate. The last few percents will probably require human intelligence.