1. H.B. Nielsen, A physical interpretation of the integrand of the n-point Veneziano model, Nordita preprint, (1969).
2. H.B. Nielsen, An almost physical interpretation of the integrand of the n-point Veneziano model, preprint at Niels Bohr Institute.
3. H.B. Nielsen, paper presented at the 15th International Conference on High Energy Physics, Kiev Ukraine (1970), V. Shelest ed., Naukoa Dumka, Kiev U.S.S.R. (1972) as second part “Veneziano’s talk”, pg. 445.
4. Y. Nambu, Quark model and the factorization of the Veneziano amplitude, in Proceedings of the International Conference on Symmetries and Quark Models, June 18-20 1969, R. Chand ed., Gordon and Breach, New York U.S.A. (1969), pg. 269, reprinted in Broken Symmetry Selected Papers of Y. Nambu, T. Eguchi and K. Nishijima eds., World Scientific, Singapore (1995), pg. 258.
5. Y. Nambu, Duality and hadrondynamics, lecture notes prepared for Copenhagen summer school, 1970, reproduced in Broken symmetry, selected papers of Y. Nambu, T. Eguchi and K. Nishijima eds., World Scientific, Singapore (1995), pg. 280.