conmemorativos del Centenario de la Primera Guerra Mundial. Actas (in Spanish). Zaragoza: Institución "Fernando el Católico", Excma. Diputación de Zaragoza. pp. 275–287...

events occurred in September 1917: Battle of Jugla – The Russian Twelfth Army fortified the banks of the Mazā Jugla river in Latvia in an attempt to slow the...