VERRINDER, James. Gallup International Association and WIN Network strike merger deal [online]. research-live.com, 2010-05-12 [cit. 2023-07-29]. Dostupné online. (angličtina)
web.archive.org
The Gallup International and WIN associations Unite [online]. gallup-international.com, 2010-07-30, rev. 2011-05-15 [cit. 2023-07-29]. Dostupné v archivu pořízeném dne 2011-05-14. (angličtina)
