Before revision: Irvin Rock and Steve Palmer, who is acknowledged as having built upon the work of Max Wertheimer and others and to have identified additional grouping principles, note that Wertheimer's laws have come to be called the "Gestalt laws of grouping" but state that "perhaps a more appropriate description" is "principles of grouping.
After revision: Irvin Rock and Steve Palmer, who are acknowledged as having built upon the work of Max Wertheimer and others and to have identified additional grouping principles, note that Wertheimer's laws have come to be called the "Gestalt laws of grouping" but state that "perhaps a more appropriate description" is "principles of grouping.