@article {IOPORT.50169351,
    author       = {Coquand, Thierry},
    title        = {Minimal invariant spaces in formal topology},
    year         = {1997},
    journal      = {J. Symb. Log.},
    volume       = {62},
    number       = {3},
    pages        = {689-698},
    identifier   = {50169351},
}