"Paper delivered at the R&D Management Association Conference on the State of the Art in R&D Management, Manchester Business School, July 11-13, 1988."--p. 1.

Includes bibliographical references (leaf [19]).

"This is a revised version of a paper which was originally delivered at the European Industrial Research Management Association Conference, Berlin, May 30, 1990. "August 1990."

Leaf number 17 omitted in paging. The research reported in this paper was supported by grants from the Office of Science Information Service, National Science Foundation and the General Electric Foundation.

"... replaces [Working paper no.] 918-77."