Effect of Total, Northern and Southern Hemisphere Sunspot Number (Ri, Rn and Rs) on F2- Layer Critical Frequencies at Mid- Latitude Rome Station During the Descending Phase of Solar Cycle 23. (2023). Iraqi Journal of Science, 57(3A), 2063-2074. https://ijs.uobaghdad.edu.iq/index.php/eijs/article/view/9962