R. Verloren van Themaat, “80 jaar ingenieursbureau J. van Hasselt en De Koning”, Raadgevend Ingenieur 1, no. 11 (1959), 230. By 1959, the firm had 188 employees on its payroll.
 Miss Groen worked for almost another 40 years for the firm, also in the accounts department. Fernhout Hanno, 125 years Royal Haskoning, 1881-2006 (2006), 31.
 The list of names of those ‘who were thus employed’ also mentioned Miss Langius (in 1919) and Miss F. Beijer (in 1920), who succeeded Miss de Graaf.
 Hettie Pott-Buter and Kea Tijdens, Vrouwen: Leven en werk in de twintigste eeuw (Amsterdam: Amsterdam University Press B.V., 1998), 158.
 When the machine was introduced in the Netherlands, the association of typewriters with women had already spread from America. The higher positions of office remained available for men. Corrie van Eijl, Het Werkzame Verschil. Vrouwen in de slag om arbeid, 1898 – 1940 (Hilversum: Uitgeverij Verloren, 1994), 48-49. For the situation in Britain, see R. Silverstone, “Office Work for Women: An Historical Review”, Business History 18, no. 1 (1976), 98-110.
 A consequence of industrialisation and increased prosperity. Men from the newly created middle-classes worked outside the house, whilst their wives stayed at home, thus copying the upper classes. From 1924 onwards in the Netherlands there was even a law banning married female public servants from working. Pott-Buter, Tijdens, Vrouwen (1998), 132.
 “Over the years, the endless reams of paper that I saw come and go in my office tell the story of the many and great works that have been accomplished here,” Van Putten wrote, DHV, Een korte terugblik (1942), 164-165.
 Royal HaskoningDHV company archives, “Verslag van de bijeenkomst ter herdenking van het vijfentwintigjarig bestaan van het ingenieursbureau Dwars Heederik en Verhey op 2 januari 1942”.
 DHV (1942), 164.
 Ibid, 164 and 218.
 The secretarial offices B and C worked for Jan Verhey (son of Bastiaan) and J.P der Weduwen respectively; in the 1960s this amounted to another five secretaries and typists. Interview with Ria Schaap and information from J. Endeman-de Kraker, 19 April 2021.
 Kea Tijdens, “Een wereld van verschil: arbeidsparticipatie van vrouwen 1945-2005”, (3 maart 2006), 4. By the 1990s this was around 30 hours.
 Els Kloek, Vrouw des huizes. Een cultuurgeschiedenis van de Hollandse huisvrouw (Amsterdam: Balans, Uitgeverij, 2009), 200.
 Votes for women was one of the most important achievements of the first wave of feminism. The original text by J.E. Kool-Smit, “Het onbehagen bij de vrouw”, De Gids 130 (1967), 267-281.
 High unemployment and economic decline in the 1970s and 1980s contributed to the breakdown of traditional ideas about the role of the bread-winner and the family in Dutch society. Also instrumental was the fact that progress in technology was making it possible to perform household tasks in an increasingly shorter time. Pott-Buter, Tijdens (1998), 140-141.
 Ibidem, 142.
 HASKONING-INFORMATIEF no. 2 (June 1985), company archives RHDHV. The Centrale Diensten had 60 employees, 40 of whom were women. At the time, Haskoning’s total workforce amounted to 458 employees.
 HASKONING-INFORMATIEF no. 2 (June 1985), company archives RHDHV.
 Ibid. At DHV the situation and mood was largely similar. One female employee in the word-processing centre (TVC) said: “Yes, we are but unimportant figures and that is reinforced when you read an annual report and see that not one single line is devoted to the TVC.” Overdwars 1, no. 18 (3 November 1977), 5, company archives RHDHV.
 Haskoning and DHV followed the same trend and hardly differed from each other in this respect. This is my conclusion after studying the (scant) figures available.
 The effect of a new phenomenon: part-time work. Introduced as a measure to combat unemployment, nowhere in the world did part-time work gain such a foothold as in the Netherlands. In short, the working girl from the early years became a part-time working mother.
 HAKOERIER (september 1992). In 1992, the workforce at Haskoning totalled 589 employees.
 DHV (1942), 220.
 She qualified at the Delft school of engineering and was amongst the first 20 Dutch female chemical engineers to graduate. Marina van Damme-van Weele en Jacobien Ressing-Wolfert, Vrouwen in techniek: 90 jaar Delftse vrouwelijke ingenieurs (Delft: Delftsche Uitgevers, 1995), 15.
 Van Damme-van Weele, Ressing-Wolfert, Vrouwen in techniek (1995), 102.
 Zwanenburg became assistant project manager in the Environmental Planning (Ruimtelijke Ordening) department, and was, alongside the female secretarial staff, its only woman [engineer]. Overdwars 3, no. 13 (18 October 1979), 8, company archives Royal HaskoningDHV.
 HAKOERIER September 1992, p 28-29.
 Source: Marie-Cecile Rossen. IWACO was a firm of consultants specialising in groundwater studies and water supplies. At the time part of De Weger group, the company was taken over by Royal Haskoning in 1997.
 Regarding Goedmakers, see: https://www.huffpost.com/entry/women-in-power-annemarie-_b_884448?ir=Women.
 Comparable to the emergence of ‘typewriting’. See story 6 in this series, about the rise in the number of women environmental scientists in the UK.
 Figures from DHV.
 Tijdens (2005), 14.
 Interview with Jan Bout. After this experience, Bout (now retired) made known in 2015 that he was a firm advocate for the introduction of so-called quotas for women. See, for example: https://fd.nl/weekend/1316561/doet-u-mij-toch-maar-een-vrouwenquotum-tle1caEY1IiX.
 Cobouw, “Eerste vrouw in top Royal Haskoning geen excuus-Truus” (7 December 2007). In fact, this was not true, since her gender was of course a condition of her appointment.
 Anonymously held source in Riëlle Nij Bijvank, Een ‘female touch’ in een mannenomgeving, final-year study (2009), 49..
 Figures from March 2021. Note: the 93 women who have no designated ‘job family’ have not been taken into account.
 Interview with Rika Praduyani. Econometrist Jaska de Bakker was CFO from 2010 to 2016 and was succeeded by Nynke Dalstra RC, CFO from 2016 to 2019.
 Interviews with Esther Kromhout and Marije Hulshof.
 Interview with Sheilla de Carvalho.