The three authors are researchers with Ph.D.s in their respective fields in psychology. They have extensive histories of publishing research articles and conduct research in their respective universities in the United States and Canada. The article summarizes existing literature that relates chronic musculoskeletal pain with fear and avoidance, reviews research into how anxiety sensitivity promotes pain-related avoidance, and suggests directions for future research. The intended audience is other researchers studying the influence of avoidance on chronic pain. This article was published in the Clinical Psychology Review journal and therefore valid as a source. The content discusses research into the fear-avoidance model and therefore is extremely relevant. ^[1]

The four authors are experienced researchers with Ph.D.s in psychology and medicine. They are internationally recognized researchers from countries around the world. The article reviews the current research into the fear-avoidance model and proposes changes to improve its clinical applications. The intended audience is physicians interested in using the fear-avoidance model for back-pain patients. This article was published in The Clinical Journal of Pain and therefore valid as a source. The content evaluates the fear-avoidance model and is extremely relevant. ^[2]

The two authors are practicing psychologists and researchers but are not affiliated with universities. They do not have an extensive history of publishing articles. The article describes the feedback loops in the fear-avoidance model and simplifies the model for the general public's understanding. The intended audience is anxiety patients seeking information about their conditions. This article was not published in a journal but rather posted in the authors' personal website, so it is somewhat valid as a source, given that the authors' credentials are authentic. The content simplifies the fear-avoidance model and is relevant. ^[3]