2026-07-072026-07-07http://salesiana.dossiersoluciones.com/handle/123456789/45347Based on a simple model which is compatible with the idea of the static quark model and the parton model, the polarized structure functions of proton and deuteron, two-spin asymmetries of $π^0$ in polarized $pp$ reactions and inelastic $J/ψ$ productions in polarized lepton-proton collisions are analyzed. In particular, an important role of polarized gluon distributions is pointed out.10 pages(Latex), 7 figures not included but available upon request (Invited talk presented at the XII International Seminar on High Energy Physics Problems- Relativistic Nuclear Physics and Quantum Chromodynamics-, Dubna, 12-17 September, 1994: to appear in the proceedings.)High Energy Physics - Phenomenologytext