@article{MZ_1976__151_172446,
     author = {Frank Levin and Benjamin Baumslag},
     title = {A {Free} {Product} with a {Non-Power} {Amalgamated} which is not {Residually} {Free.}},
     journal = {Mathematische Zeitschrift},
     pages = {235--238},
     publisher = {mathdoc},
     volume = {151},
     year = {1976},
     zbl = {0325.20030},
     url = {http://geodesic.mathdoc.fr/item/MZ_1976__151_172446/}
}