FORESIGHT AND HINDSIGHT ON A PUNCH-CARD BIBLIOGRAPHY.

The article focuses on innovations in the field of punched card systems and modifications done in order to make a punched card bibliography. The underlying technique of hand-punched, hand-sorted cards is based on the fact that if a needle is thrust through a given hole in a pack of cards all notched for that hole will fall out, leaving the unnotched cards securely on the needle. If a redesigned card could have 73 holes as a double-row series and 73 in a single-row series, the authors' present anticipated needs for a punched card bibliography would be satisfied.