@article{10_37236_4096,
     author = {P\'eter Csikv\'ari and Zhicong Lin},
     title = {Graph homomorphisms between trees},
     journal = {The electronic journal of combinatorics},
     year = {2014},
     volume = {21},
     number = {4},
     doi = {10.37236/4096},
     zbl = {1298.05062},
     url = {http://geodesic.mathdoc.fr/articles/10.37236/4096/}
}