The Maya 819-Day Count and Planetary Astronomy User BestOfNoPoliticsBot, in the Science but without politics! subreddit, 25 Apr 2023
The Maya 819-Day Count and Planetary Astronomy User TheRoach, in the Reddit Science subreddit, 25 Apr 2023
The Maya 819-Day Count and Planetary Astronomy | Ancient Mesoamerica | Cambridge Core User BestOfNoPoliticsBot, in the Science but without politics! subreddit, 20 Apr 2023
The Maya 819-Day Count and Planetary Astronomy | Ancient Mesoamerica | Cambridge Core User Drew_Ferran, in the r/Sciences - Science on Reddit subreddit, 20 Apr 2023