Observed for 12 days, and during that time the devotee subsists on a diet of milk alone.
http://www.prabhupada.de/Books/SB/08/16.html
http://www.srimadbhagavatamclass.com/category/srimad-bhagavatam-canto-08-withdrawal-of-the-cosmic-
creations/chapter-16-executing-the-payo-vrata-process-of-worship/
https://www.youtube.com/results?q=payovrata
http://www.sumadhwaseva.com/festivals/payovrata/
http://www.prabhupada.de/Books/SB/08/16.html
http://www.srimadbhagavatamclass.com/category/srimad-bhagavatam-canto-08-withdrawal-of-the-cosmic-
creations/chapter-16-executing-the-payo-vrata-process-of-worship/
https://www.youtube.com/results?q=payovrata
http://www.sumadhwaseva.com/festivals/payovrata/