Royal HaskoningDHV archives, files on Brug over de Nijl bij Embabeh. Profiel van de Nijl bij Cairo, 17 juni 1889.
 Established in 1798, Rijkswaterstaat had overall responsibility on behalf of the state for water management in the Netherlands. Over the years its responsibilities expanded to include other forms of infrastructure. Rijkswaterstaat's official name in English is the Directorate-General for Public Works and Water Management.
 ‘Normalisation’ of rivers became common in the 19th century and was a way controlling hitherto unpredictable river flows through canalisation.
 R.A. van Sandick 1906, J.M.K. Pennink 1917. In 1899, W.S.G.T. Post became De Koning’s new partner.
 Frederik Willem Conrad presided over an international commission of engineers which advised the vice-roy of Egypt about this huge project, which had been proposed by the French consul and engineer, De Lesseps. Frederik Willem Conrad, Reizen naar de landengte van Suez, Egypte, het Heilige land, The Hague, 1859, p. 2.
 The ruling Khedive had ran up a significant national debt, owing not only to his investment in modernisation programmes, but also because of his exotic hobbies.
 De Ingenieur, vol. 4, no 14, 1889, p. 120.
 That corresponds to 22 million euros by 2011 standards.
 Robert Warschauer was the son of the bank’s founding father and acted as client for De Koning.
 In 1888, Snethlage was chief engineer with the recently established Netherlands–South African Railway Company (NZASM - Nederlandsch-Zuid-Afrikaansche Spoorwegmaatschappij). It was a company in which Robert Warschauer & Co. and the Berliner Handelsgesellschaft were also involved. In memoriam N.Z.A.S.M, Amsterdam, 1908, pp. 9-10.
 The journal was inaugurated in 1886 and is still in existence today. See De Ingenieur, vol. 1, 1886, no 1.
 De Ingenieur, vol. 4, no. 16, p 140.
 Company archives Royal HaskoningDHV, Brug over de Nijl.
 J. van Duivendijk, ‘Brug over de Nijl bij Embabeh, Egypte’, Bruggen, 15, 2007, no. 4, pp. 12-19, p 12. De Koning and Van Hasselt had together written the section on ‘Bridges’ in the standard guide to hydraulic engineering (‘Waterbouw’) by Professor N.H. Henket.
 “von ihnen die niedrigst mögliche Offerte gemacht wird”, Company archives Royal HaskoningDHV, Correspondentie 1889, pp. 232-233. Letter from De Koning to R. Warschauer u C in Berlin, 15 July 1889 and letter to R.A.I. Snethlage, 21 August 1889.
 Company archives Royal HaskoningDHV, Brug over de Nijl. Incl. letter sent to De Koning by Harkort, 13 July 1889.
 This was equivalent to 4,222 Egyptian pounds.
 De Ingenieur, vol. 5, no. 2, 1890, p 18.
 ‘Financieele berichten’ in Het Vaderland, 31-12-1889.
 “Une voie ferrée, deux voies charretieres et deux trottoirs marque la conquête absolue, définitive du fleuve par l'industrie moderne” ‘Un pont sur le Nil’, Le Magasin Pittoresque, 1891, pp. 263-264.
 This resulted in no fewer than 17 piers! Lionel Wiener, L’Égypte et ses chemins de fers, Bruxelles, 1932, pp. 191-196.
 One gratifying and mischievous conclusion to the demise of the 1890 bridge might be: you pays your money and you takes your choice.
 See e.g. Royal Haskoning 1881-2006, 2006.
 That is the equivalent of more than 35,000 euros (2011 levels). Company archives Royal HaskoningDHV, Brug over de Nijl. Contract between Robert Warschauer & Co. and the Berliner Handelsgesellschaft and J. de Koning, June 1889.