Unramified quadratic extensions of a quadratic field
The authors determine all quartic number fields \(L/\mathbb{Q}\) possessing a quadratic subfield \(\mathbb{Q}\subset K\subset L\) such that \(L/K\) is unramified at all finite primes. They do this by an explicit calculation of the generators and make no use of Hilbert's theory.
scientific article; zbMATH DE number 796901