@article{10_1017_S0017089500004006,
     author = {Choo, Koo-Guan},
     title = {Whitehead groups of semidirect products of free groups {II}},
     journal = {Glasgow mathematical journal},
     pages = {71--74},
     year = {1980},
     volume = {21},
     number = {1},
     doi = {10.1017/S0017089500004006},
     url = {http://geodesic.mathdoc.fr/articles/10.1017/S0017089500004006/}
}