2026-07-072026-07-07http://salesiana.dossiersoluciones.com/handle/123456789/135085Sum rules for the spin dependent structure functions corresponding to the moment at $n=0$ derived from the current algebra based on the canonical quantization on the null-plane are reviewed.12 pages, 2 figures, Contributed paper to Lepton-Photon 2007High Energy Physics - Phenomenologytext