@article{10_4153_CMB_1989_005_7,
     author = {Ross, David},
     title = {Tree self-embeddings},
     journal = {Canadian mathematical bulletin},
     pages = {30--33},
     year = {1989},
     volume = {32},
     number = {1},
     doi = {10.4153/CMB-1989-005-7},
     url = {http://geodesic.mathdoc.fr/articles/10.4153/CMB-1989-005-7/}
}