Intraindividual stability of cortisol and cortisone and the ratio of cortisol to cortisone in saliva, urine and hair Zhang, Q.; Chen, Z.; Chen, S.; Xu, Y.; Deng, H. Steroids 118: 61-67 2017 1878-5867 10.1016/j.steroids.2016.12.008 https://eurekamag.com/research/059/879/059879214.php