Columbus Treks and Expeditions (P) Ltd - Trekking and tour options with a profile of the company, details on a packing list, physical conditioning and some extensions to Sikkim and Tibet. - http://www.columbustreks.com/
Cho-Oyu Trekking and Mountaineering - Adventure activities highlighting treks and mountaineering with details on physical conditioning. - http://www.cho-oyutrekking.com/