Although Ramanujan's assertion later had to be corrected slightly by the elision of the diagonal form [1; 2; 5; 5], it aroused great interest in the problem of enumerating all the universal quaternary forms, which was eagerly taken up, by Gordon Pall and his students in particular. In 1940, Pall also gave a complete system of invariants for the genus, while simultaneously Burton Jones found a system of canonical forms for it, so giving two equally definitive solutions for a problem raised by Smith in 1851.