@article{MS2_1977__40_166512,
     author = {C.T. Ng},
     title = {Universal parallel composition laws and their representations.},
     journal = {Mathematica Scandinavica},
     pages = {25--45},
     publisher = {mathdoc},
     volume = {40},
     year = {1977},
     zbl = {0366.94058},
     url = {http://geodesic.mathdoc.fr/item/MS2_1977__40_166512/}
}