%0 Book Section %B Rigorous quantum field theory %D 2007 %T Massless scalar field in a two-dimensional de Sitter universe %A Marco Bertola %A Corbetta, Francesco %A Moschella, Ugo %B Rigorous quantum field theory %S Progr. Math. %I Birkhäuser %C Basel %V 251 %P 27–38 %G eng