@article{MS2_1976__38_166451,
     author = {Philip Olin},
     title = {Free products and elementary types of {Boolean} {Algebras.}},
     journal = {Mathematica Scandinavica},
     pages = {5--23},
     publisher = {mathdoc},
     volume = {38},
     year = {1976},
     zbl = {0339.06008},
     url = {http://geodesic.mathdoc.fr/item/MS2_1976__38_166451/}
}