Measurements of azimuthal cross-section asymmetries from deeply virtual Compton scattering on transversely and longitudinally
polarized hydrogen and longitudinally polarized deuterium targets at HERMES are reported. By comparing the HERMES results
on the transverse target-spin asymmetry with theoretical calculations based on a phenomenological model of generalized parton
distributions, a model-dependent constraint on the total angular momentum carried by quarks in the nucleon is obtained.