Erdös, L. (2000). The kernel of Dirac operators onhttps://doi.org/10.1090/amsip/016__and . In Differential Equations and Mathematical Physics (Vol. 16, pp. 111–119). American Mathematical Society.https://doi.org/10.1090/amsip/016 
LibreCat: https://research-explorer.ista.ac.at/record/2710
DOI: 10.1090/amsip/016
arXiv: math-ph/0001036