1. NHS Digital: https://digital.nhs.uk/data-and-information/publications/statistical/fit-notes-issued-by-gp-practices/june-2018
2. Preliminary Findings on the Importance of Kinetic Oxygen in Managing the Impact of Stress. Dr C J Bowen, 2018
3. Harmful Singlet Oxygen can be helpful. Hulten LM, Holmstrom M, Soussi B, Free Radic Biol Med. 1999 Dec; 27(11-12):1203-7.
4. Report on a two-stage controlled study, using heart-rate-variability-measurements (HRV) in respect of the effectiveness of Airnergy+ Oxygen-Therapy, Dr Ulrich Knop, 2003
5. Concentrated Oxygen and Activated Respiratory Air: A comparison between the physiological effects of two inhalation applications. A study involving healthy test persons. Dr C Schollmann, 2004, Die Naturheilkunde No. 2 / 2004
6. Breier, A., Albus, M., Pickar, D., Zahn, T. P.,Wolkowitz, O.M., & Paul, S.M. (1987). Controllable and uncontrollable stress in humans: Alterations in mood and neuroendocrine and psychophysiological function. American Journal of Psychiatry, 144, 1419-1425.
7. Dolan, R. J., Calloway, S. P., Fonagy, P., De Souza, F. V. A., & Wakeling, A. (1985). Life events, depression and hypothalamic-pituitary-adrenal axis function. British Journal of Psychiatry, 147, 429-433.
8. Dinan, T.G. (1994).Glucocorticoids and the genesis of depressive illness: A psychobiologicalmodel. British Journal of Psychiatry, 164, 365-371.