@article{MM2_1983__45_154976,
     author = {Heinz O. Cordes},
     title = {A {Pseudo-Algebra} of {Observables} for the {Dirac} {Equation.}},
     journal = {Manuscripta mathematica},
     pages = {77--106},
     publisher = {mathdoc},
     volume = {45},
     year = {1983},
     zbl = {0562.35079},
     url = {http://geodesic.mathdoc.fr/item/MM2_1983__45_154976/}
}