Special thanks to Andrei Mogutov for his assistance in generating maps with the Resseau-Lu software package.
The Issuecrawler web tool can be found at http://www.issuecrawler.net
References for Scientific Papers
Abstracts and records for papers published from 1973 onward were retrieved from the ISI Web of Science
Key papers published prior to 1973:
G. Veneziano, Nuovo Cimento A 57, 190 (1968).
Y. Nambu in Proceedings of the International Conference on Symmetries and Quark Models, Wayne State Univ., June 1969, ed. Ramesh Chand (Gordon and Breach Science Publ., 1970)
L. Susskind, Nuovo Cimento A 69, 457 (1970).
H. Nielsen, XV International Conference on High Energy Physics (Kiev, 1970).