Alexander S. Kechris. On Projective Ordinals. Journal of Symbolic Logic, 39(2):269-282, 1974.
@article{Kechris74, title = {On Projective Ordinals}, author = {Alexander S. Kechris}, year = {1974}, researchr = {https://researchr.org/publication/Kechris74}, cites = {0}, citedby = {0}, journal = {Journal of Symbolic Logic}, volume = {39}, number = {2}, pages = {269-282}, }