for $article in collection("3208-2017-v2")//item/(description|titre)
for $element in $article/article/element
let $frere1:= $element/following-sibling::element[1]
let $frere2:= $element/following-sibling::element[2]
where (($element/data[1]="NOM")and ($frere1/data[1]="PRP")and ($frere2/data[1]="NOM"))
return string-join(($element/data[3],$frere1/data[3],$frere2/data[3])," ")