H. Buyter, Bierbrouwerijen, 1994, pp. 5-7.
 K . Sluyterman en B. Bouwens, Heineken: 150 jaar brouwerij, merk en familie, pp. 78 - 86.
 At least until 1975, when the new brewery was opened in Zoeterwoude and the Rotterdam production facility was closed. Ibid., pp. 320-325.
 The name of the public limited company between 1873 and 1972.
 Heederik family archive, Certificate of appreciation with the signatures of 18 colleagues at the engineering firm of Schotel .
 Feltmann arrived in Rotterdam in 1873 and died there in 1897.Originally German, as head brewer he was the driving force behind innovations at HBM during this period. H.W. Lintsen (ed.), Geschiedenis van de Techniek in Nederland. De wording van een moderne samenleving 1800-1890. Deel 1, Zutphen, 1992, p. 196..
 Stadsarchief Amsterdam, Archief Heineken N.V., nummer toegang 834, inventarisnummer 1223. Letter from Schotel to Feltmann, 16-1-1893.
 These toilets are incidentally missing in the list of works summarised in DHV. Een korte terugblik op den arbeid van het ingenieursbureau Dwars, Heederik en Verhey, 1942, pp. 61-64.
 At the time, in the Netherlands there were five breweries with more than 100 employees. Sluyterman & Bouwens, 2014 pp. 116-122 and H. Buiter, Bierbrouwerijen, PIE reports 6, Zeist, 1994, p. 7.
 The insides of all wooden casks were pitched to prevent the beer going off.
 DHV, 1942, p. 64.
 J.L. Schippers, Bouwt in beton!, 1995, pp. 9-12.
 Ibidem, pp. 13-20.
 Verhey had worked for a year at Van Waning & Co, a Rotterdam-based firm and pioneer in the field of reinforced concrete constructions and manufacturer of reinforced concrete (sewage) pipes. See Schippers, 1995, p. 15 and D. Hillenius, De geschiedenis van het Technisch Adviesbureau voor de Vereniging van Nederlandse Gemeenten, Alphen aan de Rijn, 1992, p. 13.
 In 1912 the first Reinforced Concrete Regulations were published. Schippers, p 42. The concrete link, according to Groothoff, sowed the seeds of the engineering firm that later ensued. See also D.H.V. bericht, Amersfoort, November 1967, pp.4-5.
 A. Groothoff acquired two huge assignments: an investigative study for Kennemer Elektriciteitsmaatschappij (an electricity company), and a dyke improvement scheme in Drechterland. A. Groothoff, ‘Het verhaal van D.H.V.’s geboorte’, manuscript, 1965. Company archives Royal HaskoningDHV.
 Hillenius, 1992, p. 19.
 The son of his brother who died in 1904. A widower himself and father of 2, A.D. Heederik took into his home the widow of his brother, Henriette de Wolf, and her two children. In 1919 he married her.
 Even more interesting is the sequel in which was written that a son could claim this entitlement. Heederik family archive, contract complete with signatures, undated.
 The purpose of this was described thus: ‘providing advice, the working out of plans and overseeing the execution of engineering work in the field of civil and urban planning, hygiene, hydraulics and road-building, agriculture and water management, both at home and abroad’ D.H.V. bericht, Amersfoort, November 1967.
 Including Henry Heineken, managing director and son of the founder Gerard. K. Sluyterman and B. Bouwens, 2014, p. 150.
 Ibidem pp. 137-169.
 ’Het nieuwe ziederijgebouw van de Heinekensbrouwerij’, Rotterdams Nieuwsblad, 26 April 1923.
 Stadsarchief Amsterdam, Archief Heineken 834, inv.nr.1597: all drawings of the brewhouse from 1924 are signed by Heederik.
 DHV 25 jaar, p. 64.
 See o.a. Hillenius, 1992, pp. 26-27.
 Through his marriage to her, he was no longer just the boy’s uncle, but his stepfather too. In fact J.P. Heederik continued to call him ‘Uncle’. Heederik family archive and interview with his granddaughter, Ms Bosma on 23 October 2020, and great-granddaughter on 8 November 2020.
 The day previously, Dwars had resigned from the firm. In exchange for a generous pay-off, he had no objection to the continued use of his name. Heederik family archive.
 The company had previously been known as Technisch Bureau Dwars, Heederik en Verhey. Maasbode, 27/06/1931.