@article{10_1017_S0017089500000458,
     author = {McCool, James},
     title = {The order problem and the power problem for free product sixth-groups},
     journal = {Glasgow mathematical journal},
     pages = {1--9},
     year = {1969},
     volume = {10},
     number = {1},
     doi = {10.1017/S0017089500000458},
     url = {http://geodesic.mathdoc.fr/articles/10.1017/S0017089500000458/}
}