Pooja Krishan, Sethukarasi T, Suriya Praba T. “Identification and Classification of Indoor and Outdoor Environments: A Review”. International Journal of Advanced Science and Technology 29, no. 06 (May 19, 2020): 4275 - 4284. Accessed September 16, 2021. https://sersc.org/journals/index.php/IJAST/article/view/16435.