J. Agurto Zurita, R. Cáceres Saltos, C. Vaca Mendieta, and N. Jarama Solarte, “Peripheral nerve blocks for foot surgery”., Revista UG, vol. 85, no. 3-4, pp. 111–122, Sep. 1991, doi: 10.53591/rug.v85i3 y 4.530.