In the NUMBER@1 , PERSON@1 and PERSON@2 discovered that the mesons make families called Regge trajectories with masses related to spins in a way that was later understood by PERSON@3 , PERSON@4 and PERSON@5 to be the relationship expected from rotating strings .

In NUMBER@2 PERSON@3 , PERSON@4 and PERSON@5 recognized that the theory could be given a description in space and time in terms of strings .
