“But it is not time for me to die; I have not yet finished my life's work.”
Źródło: a little time before his death, as quoted by A. J. Q. Alkemade, in [Biografisch Woordenboek van Nederland, 1982, http://www.inghist.nl/Onderzoek/Projecten/BWN/lemmata/bwn5/burgers]