The present invention provides reusable envelope structures, kits for forming reusable envelope structures, and methods of using envelopes formed from such structures and kits. Reusable envelope structures can be formed and kits can be formed for converting existing envelopes to reusable envelopes in...http://www.google.fr/patents/US20040050918?utm_source=gb-gplus-shareBrevet US20040050918 - Environmentally friendly reusable envelope structures