From

Comparative Pharmacognostic Study of Different Parts of Withania somnifera and its Substitute Ruellia tuberosa

Luxmini. K.P.A.M.K, Dharmadasa. R.M, Samarasinghe, K. Muthukumarana. P.R.M

World Journal of Agricultural Research. 2015, 3(1), 28-33 doi:10.12691/wjar-3-1-7