Columbia subject headings:
Harvard subject headings:
Bridges--France--Pas-de-Calais--History.
Pas-de-Calais (France)--Transportation--History.
Roads--France--Pas-de-Calais--History.
World War, 1939-1945--Transportation--France--Pas-de-Calais.
Princeton subject headings:
Bridges--France--Pas-de-Calais--History--20th century.
France. Direction générale des ponts et chaussées et des mines--History.
Pas-de-Calais (France)--History, Military.
Roads--France--Pas-de-Calais--History--20th century.
Transportation and state--France--Pas-de-Calais--History--20th century.
World War, 1939-1945--Transportation--France--Pas-de-Calais.