** Steen Lykke and Frits van de Kerk, 2005, "Marine operations, the Bosphorus Crossing," "Tunnelling and Underground Space Technology" 20: 609-11.
**Steen Lykke and Frits van de Kerk, 2005, "Marine operations, the Bosphorus Crossing," "Tunnelling and Underground Space Technology" 20: 609–11.