@article{10_4153_CJM_1988_029_6,
     author = {Ward, Doug},
     title = {The {Quantificational} {Tangent} {Cones}},
     journal = {Canadian journal of mathematics},
     pages = {666--694},
     year = {1988},
     volume = {40},
     number = {3},
     doi = {10.4153/CJM-1988-029-6},
     url = {http://geodesic.mathdoc.fr/articles/10.4153/CJM-1988-029-6/}
}