by Wobbe Vegter
Published in: Brainstorm, October 2001, Vol.1:3
Interview gepubliceerd in: Thema, (Nederlands) Tijdschrift
voor Thematische Filatelie, september 2006, jaargang 19 nummer 4
Published in:
The South African Philatelist, December 2001, Vol. 77:6
ThemNews, December 2001, Vol.2, no.5
Philamath, January 2002, Vol.XXIII, no.3 [#1]
Topical Time, March-April 2002, Vol.53, no.2
[#1] Philamath is the quarterly journal of the Mathematical Study Unit (MSU)
Published in: The South African Philatelist, February 2002, Vol. 78:1
Published in: The South African Philatelist, December 2002, Vol. 78:6
Published in: ThemNews, December 2002, Vol. 3, no.5 [#2]
[#2] ThemNews is the bimonthly journal of Thematics Southern Africa
Published in:
ThemNews, February 2004, Vol. 4, no.6
Philamath, October 2007, Vol.XXIX, no.2
Reprinted with permission from the March 1, 2004, issue of
Linn's Stamp News.
Published in: ThemNews, April 2004, Vol. 5, no.1
A series of monographs published in ThemNews