Respondent learning in chronic pain Fuchs, Xaver Fuchs Xaver Becker, Susanne Becker Susanne Kleinböhl, Dieter Kleinböhl Dieter Diers, Martin Diers Martin Flor, Herta Flor Herta 156 10 2108-2109 2108-2109 Ovid Technologies (Wolters Kluwer Health) 2015 1