@article{PORMA_1967__26_4_115054,
     author = {Chao, Chong-Yun},
     title = {Some applications of a theorem of {Schur} to graphs and to a class of endomorphisms},
     journal = {Portugaliae mathematica},
     pages = {505--523},
     publisher = {mathdoc},
     volume = {26},
     number = {4},
     year = {1967},
     mrnumber = {0262115},
     zbl = {0319.20007},
     language = {en},
     url = {http://geodesic.mathdoc.fr/item/PORMA_1967__26_4_115054/}
}