The name of Baertius is on the title pages of nine of the volumes of the Acta Sanctorum; the last four of May, and of the first five of June; but to judge from the articles published in these volumes his collaboration is by no means so large as these figures would indicate. There are no articles bearing his signature either in the volumes for May nor in the fifth volume for June.
The name Baertius appears on the title pages of nine volumes of Acta Sanctorum; however, his contributions are not as extensive as these figures suggest.  There are no articles signed by him in the May or June volumes.