http://www.bnaps.org/PerfinHandbook/PerfinHandbook.htm
http://www.rpsc.org/Library/perfins/per ... icials.htm
Perfin Danimarca
http://www.norbyhus.dk/perfhist.html
Perfin Finlandia
http://www.jiv.dk/finland/perfin.php
Perfin Francia
http://www.coppoweb.com/merson/fr.perfores.php?page=A
Perfin Germania
http://www.filateliaspecializzata.it/home.html
Perfin Hong Kong
http://www.rodsell.com/hksmsic/hksmsic.html
Perfin Italia
http://www.filateliaspecializzata.it/home.html
https://www.ilpostalista.it/perfin_indice.htm
http://www.perfin.it/
Perfin Regno Unito:
http://www.angelfire.com/pr/perfinsoc/index.html
Perfin Scout
http://www.sossi.org/perfin/bsa.htm
Perfin USA
http://www.perfins.org/
Pietro
Revised by Lucky Boldrini - June 2015
Revised by Lucky Boldrini - November 2015
Revised by Lucky Boldrini - November 2017
Rev LB Sep 2020
Rev LB Dec 2020
Rev LB Nov 2022
