1. Awasthi, D.D. (2007). A Compendium of the Macrolichens from India, Nepal and Sri Lanka. Bishen Singh Mahendra Pal Singh, Dehra Dun, India, 580 pp.
2. Biju, H., R.G. Bagool & S. Nayaka (2010). Additions to the lichen flora of Kerala state 2; Parmeloid macro lichens. Jawaharlal Nehru Tropical Botanic Garden and Research Institute, Kerala, India.
3. Biju, H., R.G. Bagool & S. Nayaka (2012). Additions to the lichen flora of Kerala state 2; Graphidaceae. Jawaharlal Nehru Tropical Botanic Garden and Research Institute, Kerala, India.
4. Biju, H., R.G. Bagool & S. Nayaka (2014). New records of Graphidaceous lichens form Western Ghats, India. Indian Journal of Forestry 37(4): 477–481.
5. Management Plan Mathikettan Shola National Park (2009). First Management Plan, Mathikettan Shola National Park 2009–2018. Department of Forests and Wildlife, Govt. of Kerala.