@article{BAG_1988__26_138401,
     author = {D. Ziplies},
     title = {Circle composition and radical of multiplicative polynomial laws},
     journal = {Beitr\"age zur Algebra und Geometrie},
     pages = {185--202},
     publisher = {mathdoc},
     volume = {26},
     year = {1988},
     url = {http://geodesic.mathdoc.fr/item/BAG_1988__26_138401/}
}