TY - GEN TI - "Invisible joint" (trade mark) metal ceilings and side walls - Lock Joint-Greek, Design No. 2471. AU - Milwaukee Corrugating Company. Art Metal Ceiling Department DA - 1920s UR - https://digital.lib.uh.edu/collection/aapamphlets/item/1877/show/1664 Y2 - April 12, 2021 ER -