Nighttime sleep duration, 24-hour sleep duration and risk of all-cause mortality among adults: A meta-analysis of prospective cohort studiesXiaoli Shen, Yili Wu and Dongfeng ZhangSci. Rep. 6, 21480 (2016). DOI: 10.1038/srep21480Linksdx.doi.orgFull text on PubMed: PMC4761879PMID: 26900147Google Scholar