Rūdolfs Pērle
... that Latvian artist Rūdolfs Pērle was sent to the Caucasus front in World War I as an expert on observation balloons?
... that Latvian artist <b id="mwBK8"><a href="./Rūdolfs_Pērle" id="mwBLA" rel="mw:WikiLink" title="Rūdolfs Pērle">Rūdolfs Pērle</a></b> was sent to the <a class="mw-redirect" href="./Caucasus_Campaign" id="mwBLE" rel="mw:WikiLink" title="Caucasus Campaign">Caucasus front</a> in World <span about="#mwt58" class="nowrap" data-mw='{"parts":[{"template":{"target":{"wt":"nowrap","href":"./Template:Nowrap"},"params":{"1":{"wt":"War I"}},"i":0}}]}' id="mwBLI" typeof="mw:Transclusion">War I</span> as an expert on <a href="./Observation_balloon" id="mwBLM" rel="mw:WikiLink" title="Observation balloon">observation balloons</a>?