@article{10_1017_S0017089500008417,
     author = {Harman, Glyn},
     title = {On sparsely totient numbers},
     journal = {Glasgow mathematical journal},
     pages = {350--358},
     year = {1991},
     volume = {33},
     number = {3},
     doi = {10.1017/S0017089500008417},
     url = {http://geodesic.mathdoc.fr/articles/10.1017/S0017089500008417/}
}