Surono, S. ., K. W. . Goh, C. W. . Onn, and F. . Marestiani. “Developing an Optimized Recurrent Neural Network Model for Air Quality Prediction Using K-Means Clustering and PCA Dimension Reduction”. International Journal of Innovative Research and Scientific Studies, vol. 6, no. 2, Mar. 2023, pp. 330-43, doi:10.53894/ijirss.v6i2.1427.