Holtslag, H., Jongh, J, de, Sutton, S., Nijssen, D., Haanen, R., and Veldman, R., “Smart hygiene solutions : affordable options for household level”. Smart Centre Group, Wageningen, the Netherlands, p. 20 p. : ill., photogr., 2020.

Foppen, A.H., Holtslag, H., and Chekol, C.G., “The utility approach : extended distribution for household water filters in Ethiopia”, presented at the 03/2019, The Hague, The Netherlands, 2019, p. 8 p.: 1 fig.

Mekonta, L., Butterworth, J.A., and Holtslag, H., “Great expectations : self-supply as a formal service delivery model for rural water in Ethiopia”, presented at the 07/2015, Loughborough, UK, 2015, vol. Briefing paper 2291, p. 6 p. : 1 box, 4 photogr.

Mekonta, L., Butterworth, J., and Holtslag, H., “Self-supply as a formal service delivery model for rural water in Ethiopia : ambition, approaches, challenges and opportunities”. IRC, Addis Ababa, Ethiopia, p. 6 p., 2015.

Bouman, D., Holtslag, H., and Claasen, F., “WASH solutions for schools : a hand-out for the ARC Water schools Program”. p. 39 p.; ill.; 8 tab.; 3 fig.; 5 boxes, 2012.

Holtslag, H. and Mgina, W., “Smart techs : new options to improve WASH in schools”, in Faith in water, Salisbury, UK, July 5th – 7th 2009 : conference papers , 2009, pp. P. 111-115.

Holtslag, H. and Mgina, W., “Reducing the cost of water using smart technologies : a paper presented at the International symposium on multiple-use water services in Addis Ababa..”, presented at the 2008-11-04, S.l., 2008, p. 5 p.; 2 boxes; 6 photographs.

Holtslag, H., Fajardo, A., and Zee, J. van der, “Raising rural incomes with low-cost water technologies [paper presented at the SIMI workshop (Global initiative for small-scale irrigation) Switzerland, May 2002]”. Engineering for Developing Communities(EDC), Boulder, CO, USA, p. 2 p. : 1 tab., 2002.

Zee, J. J. van der, Fajardo Reina, A., and Holtslag, H., “The impact of farm water supply on smallholder income and poverty alleviation along the Pacific Coast of Nicaragua : a case for low cost technology solutions”. Centro de Estudios y Acción para el Desarrollo, CESADE, Managua, Nicaragua, p. 8 p. : 8 tab.