http://www.scribd.com/doc/21497898/I-K-Taimni-The-Science-of-Yoga-Yoga-Sutras-of-Patanjali
P. 233 Most of the time am unable to do that, because of allergic rhinitis, or stuff. That reeeaaally sucks! :/ It would be very important to clean(?) the shrota-s or naaDi-s, or whatever, now wouldn't it?
