@article{GDZPPN002352036, title = {On the Degrees of Universal Regressive Isols.}, journal = {Mathematica Scandinavica}, volume = {32}, year = {1973}, pages = {145-164}, zbl = {0275.02040}, url = {http://dml.mathdoc.fr/item/GDZPPN002352036} }
Ellentuck, Erik. On the Degrees of Universal Regressive Isols.. Mathematica Scandinavica, Tome 32 (1973) pp. 145-164. http://gdmltest.u-ga.fr/item/GDZPPN002352036/