(:extraire le patron NOM PRP NOM PRP :)
for $b in doc("bao2_3242.txt")//item

let $frere := $b/following-sibling::item[1] where $b/a[4] = "NC" and $frere/a[4] = "P"
let $freredefrere := $frere/following-sibling::item[2] where $frere/a[4] = "P" and $freredefrere/a[4] = "NC"
let $frere3 := $freredefrere/following-sibling::item[3] where $freredefrere/a[4]="NC" and $frere3/a[4]= "P"
return <patron>{$b/a[2]/text(), ' ', $frere/a[2]/text(), ' ', $freredefrere/a[2]/text(), ' ', $frere3/a[2]/text()}</patron>