Dr H Braun [stamped, 1975] I wanted you to know that we have now programmed the general case of the rings mentioned in our comspan[?]-device. It would be prohibitive to generate all possible isomers but if you have useful constraints I think our programs may be able to help. Have you come to the U.S.? If you are anywhere in this country we might arrange to demonstrate the programs via the computer net. Sincerely Joshua Lederberg