Sigmund Freud, Stanley Hall, Carl Gustav Jung, Abraham Arden Brill, Ernest Jones and Sándor Ferenczi. Photograph, 1909. https://www.rawpixel.com/image/13991591/photo-image-face-person-clothingFree Image from public domain licenseG. Stanley Hall. Photogravure by Synnberg Photo-gravure Co., 1898. https://www.rawpixel.com/image/13988963/stanley-hall-photogravure-synnberg-photo-gravure-co-1898Free Image from public domain licenseProfessors at Leipzig University, seen at clinical work, research and teaching: six portraits. Process print, 1908. https://www.rawpixel.com/image/14003210/image-face-person-bookFree Image from public domain license