SICLASS forecasting the European enterprise sector by industry and size class by Niels S. Bosma, TonKwaak 55 Pages, Published 1999 ISBN-13: 978-90-371-0728-9, ISBN: 90-371-0728-1
PRISMA '98 Policy Research Instrument for Size-aspects in Macro-economic Analysis by TonKwaak 89 Pages, Published 1999 ISBN-13: 978-90-371-0710-4, ISBN: 90-371-0710-9