Ker-I Ko. Relativized Polynomial Time Hierarchies Having Exactly K Levels. SIAM Journal on Computing, 18(2):392-408, 1989.
@article{Ko89:2, title = {Relativized Polynomial Time Hierarchies Having Exactly K Levels}, author = {Ker-I Ko}, year = {1989}, researchr = {https://researchr.org/publication/Ko89%3A2}, cites = {0}, citedby = {0}, journal = {SIAM Journal on Computing}, volume = {18}, number = {2}, pages = {392-408}, }