H. Alberts, Meza, R., Solis, D., y Rodriguez, M.,
«How the rope pump won in Nicaragua»,
Waterlines, an international journal of water, sanitation and waste, pp. p. 3-5: 2 tab., photogr., 1993.
J. G. Orozco, Alberts, H., Sandiford, P., y Gorter, A.,
«The Nicaraguan rope pump»,
Waterlines, an international journal of water, sanitation and waste, pp. p. 27-30: 4 fig., ill., photogr., 1993.