With co-author Remi-Armand Collaris, he wrote the Dutch book RUP op Maat, Een praktische handleiding voor IT-projecten, translated as RUP Tailored, A Practical Guide to IT Projects, second revised edition published in 2008 (see http://www.rupopmaat.nl). They are now working on a new book: ScrumUP, Agile Software Development with Scrum and RUP (see http://www.scrumup.eu).