Krassilov VA, Afonin SA, Naugolnykh SV. Permotheca with in situ pollen grains from the Lower Permian of the Urals. JPS [Internet]. 1999 Dec. 31 [cited 2024 May 5];48((1-3):19-25. Available from: https://www.jpsonline.co.in/index.php/jop/article/view/1287