Your sentence is correct, but it's not the passive voice. "Изданными/published" is a passive participle, the sentence is still in the active (or, to be more precise, in the reflexive) voice. If you want to make it passive, you should put the main verb in the passive voice. For example : "Эти статьи изданы университетом и являются одними из важнейших" (where the first part of the sentence is passive)