@article{701199,
     title = {Quaternion quantum theory as a description of tachyons and the symmetry breaking},
     booktitle = {Abstracta. 8th Winter School on Abstract Analysis},
     series = {GDML\_Books},
     publisher = {Czechoslovak Academy of Sciences},
     address = {Praha},
     year = {1980},
     pages = {155-157},
     url = {http://dml.mathdoc.fr/item/701199}
}

Souček, J. Quaternion quantum theory as a description of tachyons and the symmetry breaking, dans Abstracta. 8th Winter School on Abstract Analysis, GDML_Books,  (1980), pp. 155-157. http://gdmltest.u-ga.fr/item/701199/