For Travelers holding "L"visa can get the Tibet Travel Permit easily through tourtibet.com ,you just need to provide us the photocopy of your passport and chinese visa.Whiles for the"F"visa holders, an ivitation paper is required,which states your full name, nationality, passport number and duration of your stay. The letter should be written in Chinese on official letterhead and needs to be dated and stamped with the company's official seal(the company you will visit). This letter then needs to be scanned and emailed to us and forward to the Tibet Tourism Bureau to get your permit