A. Roger Ekirch and research on the historical practice of "segmented sleep". Interesting! I didn't know this.
Segmented Sleep. I've slept like this for years and didn't know it was "natural".
Letter of Recommendation: Segmented Sleep - NYTimes.com
Segmented Sleep with Siesta
The Guardian article: I used to be tired all the time too. 'Segmented sleep' solved that
The Calming Revelation Of Segmented Sleep
It’s not insomnia if you stay up voluntarily.
Letter of Recommendation: Segmented Sleep - The New York Times