Distribution of neuronal nitric oxide synthase in the rat liver. RodrigoJ, Uttenthal O, Peinado MA,  Esteban FJ, Fernández AP, Serrano J, Martínez-De Velasco J,  Santacana M, Bentura ML,Martínez-Murillo r, Pedrosa JA.  Journal of the Autonomic Nervous System. 70 – 3, pp. 164 – 179. Elsevier. PMID: 9159499, 1998. Available on-line at: <www.sciencedirect.com/science/