Brockhaus-1911: Clay Croß · Clay
Herder-1854: Clay
Lueger-1904: China-clay
Meyers-1905: Cornish clay · London-clay · Speeton clay · Clay · Clay Center · Clay Croß
Pagel-1901: Clay, John · Clay, Charles
Pierer-1857: Henry Clay · Weald-Clay · Clay [1] · Clay [2]