@article{10_1007_s10587_013_0050_0,
     author = {Li, Hui and Peng, Liang-Xue},
     title = {Pressing {Down} {Lemma} for $\lambda $-trees and its applications},
     journal = {Czechoslovak Mathematical Journal},
     pages = {763--775},
     publisher = {mathdoc},
     volume = {63},
     number = {3},
     year = {2013},
     doi = {10.1007/s10587-013-0050-0},
     mrnumber = {3125652},
     zbl = {06282108},
     language = {en},
     url = {http://geodesic.mathdoc.fr/articles/10.1007/s10587-013-0050-0/}
}