@article{10_4153_CMB_1973_055_6,
     author = {Stein, Sherman K.},
     title = {The {Cardinalities} of {A+A} and {A-A}},
     journal = {Canadian mathematical bulletin},
     pages = {343--345},
     year = {1973},
     volume = {16},
     number = {3},
     doi = {10.4153/CMB-1973-055-6},
     url = {http://geodesic.mathdoc.fr/articles/10.4153/CMB-1973-055-6/}
}