1. Very readable, though now outdated, is A. Borst, The Ordering of Time: from the Ancient Computus to the Modern Computer, trans. A. Winnard (Cambridge, 1993).
2. On the Supputatio Romana, see A. A. Mosshammer, The Easter Computus and the Origins of the Christian Era (Oxford, 2008), pp. 204–13;
3. L. Holford-Strevens, ‘Paschal Lunar Calendars up to Bede’, Peritia 20 (2008), pp. 165–208, at pp. 173–8.
4. Padua Biblioteca Antoniana, MS I 27, fos 76r–77v; Daniel McCarthy and D. Ó Cróinín, ‘The ‘Lost’ Irish 84-Year Easter Table Rediscovered’, Peritia pp. 6–7 (1987–88), 227–42.
5. On the Latercus, see especially Daniel McCarthy, ‘Easter Principles and a Fifth-Century Lunar Cycle used in the British Isles’, Journal for the History of Astronomy 24 (1993), 204–24;