Otgonbayar, Munkhdulam, et al. “Extending NDVI Time Series in Mongolia Using Spatial Correlation Analysis Between AVHRR-GIMMS and MODIS TERRA Data”. Mongolian Journal of Geography and Geoecology, vol. 62, no. 46, Sept. 2025, pp. 174-81, doi:10.5564/mjgg.v62i46.4133.