Digitalizzazione della copia, disponibile presso la Harvard University, a cura di Google: (http://books.google.it/books?id=O4IOAAAAYAAJ&pg=PA22&dq=Atlas+contenant+en+r%C3%A9duction+des+plans+et+profils+du+Tunnel+sous+marin+entre+l%E2%80%99Angleterre+et+la+France&hl=it&ei=aHosTIjDB4GXsQav2Oi-Ag&sa=X&oi=book_result&ct=result&resnum=5&ved=0CDMQ6AEwBA#v=onepage&q&f=false) |