Professor Isabel de Madariaga, Isabel De Madariaga, "Catherine the Great: A Short History, 2nd Edition" English | ISBN: 0300097220 | 2002 | 249 pages | PDF | 10 MB
Robert Ehrlich, Harold A. Geller, "Renewable Energy, Second Edition: A First Course, 2nd Edition" 2017 | ISBN-10: 1498736955 | 514 pages | PDF | 44 MB