Solomon Feferman, C. Spector. Incompleteness Along Paths in Progressions of Theories. Journal of Symbolic Logic, 27(4):383-390, 1962.
@article{FefermanS62, title = {Incompleteness Along Paths in Progressions of Theories}, author = {Solomon Feferman and C. Spector}, year = {1962}, tags = {C++}, researchr = {https://researchr.org/publication/FefermanS62}, cites = {0}, citedby = {0}, journal = {Journal of Symbolic Logic}, volume = {27}, number = {4}, pages = {383-390}, }