Wang QP, Koyama Y, Guan JL, Takahashi K, Kayama Y, Shioda S. The orexinergic synaptic innervation of serotonin- and orexin 1-receptor-containing neurons in the dorsal raphe nucleus. Regul Pept. 2005 Mar 15;126(1-2):35–42. doi: 10.1016/j.regpep.2004.08.030. PMID: 15620411.