Kubiś, Katarzyna, and Andrzej Nowakowski. “The Evaluation of the State of Preservation of the Regional Newspapers and Journals from the Years 1800-1939 Held in the Collection of Poznań University Library”. Biblioteka, no. 13(22), Jan. 2009, pp. 77-86, doi:10.14746/b.2009.13.4.