Asymptotic behavior and rectangular band structures in SL ( 2 , ℝ ) . Breckner, Brigitte E.; Ruppert, Wolfgang A.F. — 2001 Journal of Lie Theory
On compactification lattices of subsemigroups of SL ( 2 , ℝ ) . Breckner, Brigitte E.; Ruppert, Wolfgang A.F. — 2004 Journal of Lie Theory