Graczyk, K. Marian Małecki, “From under the Blade of the Guillotine. The Criminal Trial for Espionage in the Third Reich in the Light of the Files Concerning Gertrude Spruce and the U-2 Group of the Home Army”. Zabrze—Tarn. Góry, Inforteditions Publ. House, 2019. zdp 2020, 13, 425—430.