By the agreement of the Scientific Publishing House PWN we used here gratuitously illustrating materials of the New Public Encyclopaedia PWN including photos taken by :
Mr. J. Kilian
Mr. A. Pienkos
Mr. A. Znamierowski
We would like to thank very much the whole PWN and especially to Mrs. Grazyna Bombala (the directory’s office of PWN), to Mr. Grzegorz Boguta (the General President of PWN) and from the bottom of our hearts to Mr. Andrzej Lipka (the directory of the Illustrating Office of PWN).