In 1959, the American Embassy in Kathmandu sent the Department of State a message. The contents contained the rules and regulations set forth about expeditions about the YETI.
Here is the document -- and it's fascinating: http://www.theblackvault.com/documentarchive/american-embassy-foreign-service-despatch-to-department-of-state-regarding-the-yeti-30-november-1959/