A Quantitative Approach to Estimate both Essential and Non-essential Elements in Some Commercial Samples of Triphala churna by using WD-XRF Spectrometry, Kantamreddi, Venkata Siva Satya, V. Veni Thirumala, and Swamy G. Y. S. K. , Pharmacognosy Journal, April 2017 , Volume 9, Issue 3, p.378-381, (2017)