Ayala, I., Martos, N. F., Silvan, G., Gutierrez-Panizo, C., Clavel, J. G., & Illera, J. C. (2012). Cortisol, adrenocorticotropic hormone, serotonin, adrenaline and noradrenaline serum concentrations in relation to disease and stress in the horse. Research in Veterinary Science, 93(1), 103–107.