@article{1256049900, author = {Dyer, Micheal N.}, title = {Homotopy trees: Essential height and roots}, journal = {Illinois J. Math.}, volume = {20}, number = {4}, year = {1976}, pages = { 306-313}, language = {en}, url = {http://dml.mathdoc.fr/item/1256049900} }
Dyer, Micheal N. Homotopy trees: Essential height and roots. Illinois J. Math., Tome 20 (1976) no. 4, pp. 306-313. http://gdmltest.u-ga.fr/item/1256049900/