Adib Sofia, - (2012) Doomsday in Classical Indonesian Literary Works Exploring the Nation Wealth to Face the 21st Century. In: Proceedings International Seminar : Language, Literature, Culture, and Education in Southeast Asia II Theme "Responding to Challenges in The 21st Century". Graduate School of Linguistic USU, Sumatera Utara, pp. 761-771. ISBN 978-602-17092-0-7