From 1927–1929, Harlow Shapley and Helen Sawyer Hogg began categorizing clusters according to the degree of concentration the system has toward the core using this scale.
Helen Mirren | Helen Keller | Helen | Helen of Troy | Helen Hayes | Tom Sawyer | Sawyer Brown | Helen Clark | Helen Reddy | Helen Frankenthaler | Robert J. Sawyer | Helen Hunt | Helen Humes | The Adventures of Tom Sawyer | Pam Sawyer | James Hogg | Joanne Hogg | Helen Razer | Helen Fielding | Helen Allingham | Kyle Hogg | Helen Storrow | Helen Shaver | Helen Caldicott | Diane Sawyer | Quintin Hogg, Baron Hailsham of St Marylebone | Peyton Sawyer | Pam Hogg | Helen Sjöholm | Helen Sharman |