The Timing of the Circadian Clock and Sleep Differ between Napping and Non-Napping Toddlers.
Akacem LD, Simpkin CT, Carskadon MA, Wright KP, Jenni OG, Achermann P, LeBourgeois MK. The Timing of the Circadian Clock and Sleep Differ between Napping and Non-Napping Toddlers. PLoS One. 2015; 10(4):e0125181.