Study title

General practitioners opinions on, experiences with weekend service / frequency, duration of weekend duty / cooperation with colleagues in "weekend duty organization" / exchange of information about patients / opinion on weekend patients / number and geographic location of patients / differences in treatment of patients / ( dis )satisfaction of patients with treatment / data on weekend patients complaints, emergencies, treatments, etc. / tasks of G.P.'s in general / patients experiences with weekend health service / motivation to contact G.P. during weekend / perceived seriousness of various symptoms, urgency to contact G.P.. Background variables: basic characteristics/ residence/ organizational membership