Columbia subject headings:
Petersburg Crater, Battle of, Va., 1864.
United States--History--Civil War, 1861-1865--Registers.
Virginia--History--Civil War, 1861-1865.
Harvard subject headings:
Petersburg Crater, Battle of, Va., 1864.
United States--History--Civil War, 1861-1865--Registers.
Virginia--History--Civil War, 1861-1865--Campaigns.
Princeton subject headings:
Petersburg (Va.)--History.
United States--History--Civil War, 1861-1865--Campaigns.
Virginia--History--Civil War, 1861-1865--Campaigns.