Analysis of information sources in references of the Wikipedia article "Liu Yongfu" in English language version.
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: CS1 maint: location missing publisher (link)(Original from Harvard University)For over a year prior to China's 'unofficial' declaration of war in 1884, Liu Yung-fu's 'Black Flag' forces effectively harassed the French at Tongking, at times fighting behind entrenched defences or else laying skilful ambushes.