Abstract: In a continuous assembly of mailers or items of postal correspondence with incorporated documents, the incorporated document in each mailer is constituted by a leaf comprising a top flange and a detachable portion or by a pad of such leaves, not necessarily of the same dimensions, joined through their flanges and provided if necessary with selective transfer means from one leaf to the other, or again by a pad composed of heterogeneous elements. The latter may be leaves, folded printed forms with crossed or uncrossed folds, return envelope, fascicles, plastic cards or the like joined together by respective detachable flanges formed or fastened at the top of said elements. The assembly has a continuous base strip divided into panels, each panel being bounded by two transverse lines of weakness provided for the accordion-folding of the strip. Each incorporated document is fastened to a respective panel by glueing at the top transversely to the strip.