Columbia subject headings:
Harvard subject headings:
Copyright.
Legal deposit of books, etc.--United States--History--19th century.
Legal deposit of books, etc.--United States--History--20th century.
Library of Congress--History--19th century.
Library of Congress--History--20th century.
National libraries--Collection development--Washington (D.C.)--History--19th century.
National libraries--Collection development--Washington (D.C.)--History--20th century.
Princeton subject headings:
Legal deposit of books, etc.--United States--History--19th century.
Legal deposit of books, etc.--United States--History--20th century.
Library of Congress--History--19th century.
Library of Congress--History--20th century.
National libraries--Collection development--Washington (D.C.)--History--19th century.
National libraries--Collection development--Washington (D.C.)--History--20th century.