Description
Related Subjects
The graph displays the other subjects mentioned on the same pages as the subject "Birdwood, William Riddell". If the same subject occurs on a page with "Birdwood, William Riddell" more than once, it appears closer to "Birdwood, William Riddell" on the graph, and is colored in a darker shade. The closer a subject is to the center, the more "related" the subjects are.