Astronomy & Astrophysics Astronomy and astrophysics, 648. EDP Sciences Astronomy and Astrophysics, 648, 1-16 Morganti, R, Oosterloo, T A, Brienza, M, Jurlin, N, Prandoni, I, Orru, E, Shabala, S S, Adams, E A K, Adebahr, B, Best, P N, Coolen, A H W M, Damstra, S, de Blok, W J G, de Gasperin, F, Denes, H, Hardcastle, M, Hess, K M, Hut, B, Kondapally, R, Kutkin, A M, Loose, G M, Lucero, D M, Maan, Y, Maccagni, F M, Mingo, B, Moss, V A, Mostert, R I J, Norden, M J, Oostrum, L C, Röttgering, H J A, Ruiter, M, Shimwell, T M, Schulz, R, Vermaas, N J, Vohl, D, van der Hulst, J M, van Diepen, G M, van Leeuwen, J & Ziemke, J 2021, ' The best of both worlds: Combining LOFAR and Apertif to derive resolved radio spectral index images ', Astronomy and Astrophysics, vol. 648, A9, pp. 1-16 . https://doi.org/10.1051/0004-6361/202039102 Astronomy and Astrophysics, 648:A9. EDP Sciences