Rao, A.R., and Vimala Achuthan. “Further Contribution to Our Knowledge of the Anatomy of Ptilophyllum”. Journal of Palaeosciences 16, no. (1-3) (December 31, 1967): 249–257. Accessed November 22, 2024. https://jpsonline.co.in/index.php/jop/article/view/525.