Samson, Jim (1979–1980). "Szymanowski: An Interior Landscape". Proceedings of the Royal Musical Association. 106: 69–76. doi:10.1093/jrma/106.1.69. JSTOR765927.
Wightman, Alastair (July–October 1995). "Themes of Duality and Transformation in Szymanowski's King Roger". Music Analysis. 14 (2/3): 257–291. doi:10.2307/854015. JSTOR854015.
Samson, Jim (1979–1980). "Szymanowski: An Interior Landscape". Proceedings of the Royal Musical Association. 106: 69–76. doi:10.1093/jrma/106.1.69. JSTOR765927.
Wightman, Alastair (July–October 1995). "Themes of Duality and Transformation in Szymanowski's King Roger". Music Analysis. 14 (2/3): 257–291. doi:10.2307/854015. JSTOR854015.