Rodney G. Downey. On Pi::1:::::0::: Classes and their Ranked Points. Notre Dame Journal of Formal Logic, 32(4):499-512, 1991.
@article{Downey91, title = {On Pi::1:::::0::: Classes and their Ranked Points}, author = {Rodney G. Downey}, year = {1991}, researchr = {https://researchr.org/publication/Downey91}, cites = {0}, citedby = {0}, journal = {Notre Dame Journal of Formal Logic}, volume = {32}, number = {4}, pages = {499-512}, }