@article{10_4064_cm88_2_2,
     author = {J. D. Monk},
     title = {Generalized free products},
     journal = {Colloquium Mathematicum},
     pages = {175--192},
     publisher = {mathdoc},
     volume = {88},
     number = {2},
     year = {2001},
     doi = {10.4064/cm88-2-2},
     language = {en},
     url = {http://geodesic.mathdoc.fr/articles/10.4064/cm88-2-2/}
}