Steffens, F.Thomas, A.2006-07-052006-07-051997Australian Journal of Physics, 1997, vol.50, iss.1, pp.71-780004-9506http://hdl.handle.net/2440/10835We give an overview of present calculations involving the proton spin structure function. It is shown that a significant part of the discepancy between the data and the Ellis-Jaffe sum-rule may arise through the axial anomaly if the gluons within the proton are strongly polarized. While a quark model, such as the MIT bag, does not include the anomaly, and therefore cannot be expected to reproduce the spin structure function, it does give a rather good description of recent data which is anomaly free, such as the distribution of polarized, valence up-quarks in the proton.enConference paper0030004506001997223010.1071/P96044A1997WE325000092-s2.0-724423126368512Thomas, A. [0000-0003-0026-499X]