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Jacobsen, Mark; Levine, Robert; Schwabe, William (1985). "Belgian policy". Contingency plans for war in Western Europe, 1920–1940. Santa Monica, CA: Rand. p. 130. CiteSeerX10.1.1.904.7376. ISBN0-8330-0661-4. OCLC12215643.
worldcat.org
Jacobsen, Mark; Levine, Robert; Schwabe, William (1985). "Belgian policy". Contingency plans for war in Western Europe, 1920–1940. Santa Monica, CA: Rand. p. 130. CiteSeerX10.1.1.904.7376. ISBN0-8330-0661-4. OCLC12215643.