The Apery algorithm for a plane singularity with two branches. Barucci, Valentina; D'Anna, Marco; Fröberg, Ralf — 2005 Beiträge zur Algebra und Geometrie
A note on the Stanley-Reisner ring of a join and of a suspension. Ralf Fröberg — 1988 Manuscripta mathematica
A study of graded extremal rings and of monominal rings. Ralf Fröberg — 1982 Mathematica Scandinavica
Maximality properties for one-dimensional analytically irreducible local Gorenstein and Kunz rings. Ralf Fröberg; Valentina Barucci — 1998 Mathematica Scandinavica