@article{BAG_1986__22_138332,
     author = {Herbert Lugowski},
     title = {On free {Turing} algebras},
     journal = {Beitr\"age zur Algebra und Geometrie},
     pages = {5--28},
     publisher = {mathdoc},
     volume = {22},
     year = {1986},
     zbl = {0615.08004},
     url = {http://geodesic.mathdoc.fr/item/BAG_1986__22_138332/}
}