Response by Baekgaard et al to Letters Regarding Article, "The Effects of Public Access Defibrillation on Survival After Out-of-Hospital Cardiac Arrest: A Systematic Review of Observational Studies". Issue 15 (10th April 2018) - Baekgaard, Josefine S.; Viereck, Søren; Møller, Thea Palsgaard; Ersbøll, Annette Kjær; Lippert, Freddy; Folke, Fredrik