In Hinsley, F.H. British Foreign Policy Under Sir Edward Grey. Cambridge University Press. p. 324. ISBN 978-0-521-21347-9. ↑ Clark (2013), p. 157. ↑ Clark (2013), p. 242. ↑ Williamson (1991), pp. 125–140. ↑ Williamson (1991), pp. 143-145. ↑ Williamson (1991), pp. 147-149. ↑ Williamson (1991), pp. 151-154. ↑ Wohlforth, William C.