ISBN 978-0-8147-5833-5. ↑ Clark (2013), pp. 132-136, 190-197, 301-313, 498-506. ↑ Clark (2013), p. 68. ↑ Clark (2013), pp. 77-78. ↑ Clark (2013), p. 77. ↑ Mulligan, William (2010). The Origins of the First World War. Cambridge University Press. p. 7.