American Helvetia Philatelic Society:web: www.swiss-stamps.org Union of Swiss Philatelic Societies:web: www.vsphv.ch Swiss Association of Postmark Collectors:web: www.poststempelsammler.ch Swiss Postal Stationery Collectors Club:web: www.ganzsachen.ch Swiss Thematic Association:web: www.thema-briefmarken.ch Museum of Communication, Bern:web: http:www.mfk.ch/en/collection British Library: Philatelic Collectionsweb: www.bl.uk/collections/philatelic Consilium Philateliae Helveticaeweb: en.cphh.ch Association internationale des experts en philatelie (AIEP)web: aiep-experts.net The Royal Philatelic Society, London:web: www.rpsl.org.uk UK Philately:web: www.ukphilately.org.uk The National Philatelic Society:web: www.ukphilately.org.uk/nps The Universal Postal Union:web: www.upu.int/en.html Philatelie Liechtenstein:web: www.philatelie.li United Nations Postal Adminstration:web: unstamps.un.org Verband Briefmarken Prufer Schweiz (Swiss Association of Philatelic Experts)web: https://briefmarken-prüfer.ch/ Rhone Philatelieweb: www.rhonephilatelie.ch