@article{10_1017_S0017089500030019,
     author = {Urakawa, Hajime},
     title = {A discrete analogue of the harmonic morphism and green kernelcomparison theorems},
     journal = {Glasgow mathematical journal},
     pages = {319--334},
     year = {2000},
     volume = {42},
     number = {3},
     doi = {10.1017/S0017089500030019},
     url = {http://geodesic.mathdoc.fr/articles/10.1017/S0017089500030019/}
}