Human history in 4 volumes. Written by Professor Oscar Yeager. Volume 2: History of the Middle Ages. With 216 engravings in the text, with 16 annexes printed in black and color, three cards in the text and 6 cards in a special annex. Translated by P. N. Polevoy. SPb.: Published in publishing house of A.F. Marks, 1908 – 624 p.