References PRDpp. 105, 108 anonpp. 68–69, 150 Systempp. 1, 22, 34, 39, 49, 61–63, 94, 121, 167, 188, 203, 206–211, 219, 231, 237–238, 251, 265, 275–276, 278, 280, 282, 300, 302, 308–309, 311