Andrea Sorbi. On some filters and ideals of the Medvedev lattice. Arch. Math. Log., 30(1):29-48, 1990. [doi]
@article{Sorbi90-0, title = {On some filters and ideals of the Medvedev lattice}, author = {Andrea Sorbi}, year = {1990}, doi = {10.1007/BF01793784}, url = {http://dx.doi.org/10.1007/BF01793784}, researchr = {https://researchr.org/publication/Sorbi90-0}, cites = {0}, citedby = {0}, journal = {Arch. Math. Log.}, volume = {30}, number = {1}, pages = {29-48}, }