@article{700582,
     title = {Homomorphisms and isomorphisms of semigroups of continuous selfmaps},
     booktitle = {General Topology and Its Relations to Modern Analysis and Algebra},
     series = {GDML\_Books},
     publisher = {Academia Publishing House of the Czechoslovak Academy of Sciences},
     address = {Praha},
     year = {1971},
     pages = {175-180},
     mrnumber = {MR0278281},
     zbl = {0232.54010},
     url = {http://dml.mathdoc.fr/item/700582}
}

Magill, K. D., Jr. Homomorphisms and isomorphisms of semigroups of continuous selfmaps, dans General Topology and Its Relations to Modern Analysis and Algebra, GDML_Books,  (1971), pp. 175-180. http://gdmltest.u-ga.fr/item/700582/