(1) IVW II/2022
(2) ahgz trend survey 2021
(3) ahgz trend survey 2021
(4) ahgz reader structure analysis 2022
(1) IVW May/2022
(2) Recipient file, January 2022
(3) Followers of ahgz social media channels: Facebook, Instagram, LinkedIn, Xing, Status: May 2022
(4) own messurement CMS