The scattering amplitudes were derived systematically from the action principle by Peter Goddard, Jeffrey Goldstone, Claudio Rebbi, and Charles Thorn, giving a space-time picture to the vertex operators introduced by Veneziano and Fubini and a geometrical interpretation to the Virasoro conditions.
Amplitúdy rozdelenia boli odvodené systematicky od akčného princípu, ktorý rozvinuli Peter Goddard, Jeffrey Goldstone, Claudio Rebbi a Charles Thorn, pričom udali časopriestorový rámec pre uhlové operátory, zavedené Venezianom a Fubinim a geometrickú interpretáciu pre Virasorove podmienky.