@article{10_4153_CJM_1968_057_1,
     author = {Gr\"atzer, George},
     title = {On {Polynomial} {Algebras} and {Free} {Algebras}},
     journal = {Canadian journal of mathematics},
     pages = {575--581},
     year = {1968},
     volume = {20},
     number = {1},
     doi = {10.4153/CJM-1968-057-1},
     url = {http://geodesic.mathdoc.fr/articles/10.4153/CJM-1968-057-1/}
}