@article{DCG_1987__2_131021,
     author = {R.E. Jamison},
     title = {Direction {Trees.}},
     journal = {Discrete & computational geometry},
     pages = {249--254},
     publisher = {mathdoc},
     volume = {2},
     year = {1987},
     zbl = {0615.05026},
     url = {http://geodesic.mathdoc.fr/item/DCG_1987__2_131021/}
}