@article{SF_1972__5_133938,
     author = {J.H. Carruth and C.E. Clark},
     title = {Concerning restrictions of {Green's} {H} equivalence.},
     journal = {Semigroup forum},
     pages = {186--190},
     publisher = {mathdoc},
     volume = {5},
     year = {1972},
     zbl = {0259.20057},
     url = {http://geodesic.mathdoc.fr/item/SF_1972__5_133938/}
}