@article{MS2_1965__16_165904,
     author = {Tah-Kai Hu},
     title = {On the {Bases} of {Free} {Algebras.}},
     journal = {Mathematica Scandinavica},
     pages = {25--28},
     publisher = {mathdoc},
     volume = {16},
     year = {1965},
     url = {http://geodesic.mathdoc.fr/item/MS2_1965__16_165904/}
}