Papers
Polarization-Free Generators and the S-Matrix
Hans-Jürgen Borchers, Detlev Buchholz, Bert Schroer open access link Commun.Math.Phys. 219 (2001) 125-140Global Properties of Vacuum States in de Sitter Space
Hans-Jürgen Borchers, Detlev Buchholz open access linkAnnales Poincare Phys.Theor. A70 (1999) 23-40