1. Portrait of an older man in regards to man's development. Artist is Carl Bohnen, 1871-1951. Collection: Early 20th Century Engineering Lantern Slides Set: H. I. M. (Human Interaction Management) Date: undated Format: Image Agent: unknown
2. Chart illustrating the relationship between mental age and occupation Collection: Early 20th Century Engineering Lantern Slides Set: H. I. M. (Human Interaction Management) Date: undated Format: Image Agent: unknown
3. Portrait of a middle-aged man in regards to man's development. Artist is Carl Bohnen, 1871-1951. Collection: Early 20th Century Engineering Lantern Slides Set: H. I. M. (Human Interaction Management) Date: undated Format: Image Agent: unknown
4. Portrait of a young man in regards to man's development. Artist is Carl Bohnen, 1871-1951. Collection: Early 20th Century Engineering Lantern Slides Set: H. I. M. (Human Interaction Management) Date: undated Format: Image Agent: unknown
