B. Zyska (red.), "Historia - biblioteki - informacja naukowa - papier drukowy" (S. 57-68). Katowice : Wydawnictwo Uniwersytetu Śląskiego
In the first half of the XVII century the office of the Birże Radziwills issued a great number of documents edited by the group of court secretaries, primarily a wealth of correspondence.These letters were written in Polish, German and Latin and signed by members of the Radziwiłł family, however, study of archival sources indicates that they were composed by court officials, most notably by Piotr Kochlewski, Krzysztof Arciszewski or Daniel
Naborowski. Their patrons merely indicated the general outline of the letters or ordered them to be written entirely independently by the scribe. It is not possible in today’s textual researches to make use of interna] textual evidence in these documents since sometimes they were written personally by members of the Radziwiłł family, although all the indications show that they were composed by secretaries or dominies who merely presented them to their masters to be copied out. Doubts as to authorship are also aroused in the case of the orations, declaimed by the Birże princes, but earlier prepared by the secretaries. Similar uncertainties must be taken into account when studying the Radziwiłł diaries.