[1] J. Bernd, S. Console and C. Olmos: Submanifolds and holonomy, Chapman & Hall, Boca Raton, FL, 2003.
[2] J.-H. Eschenburg: Extrinsic symmetric spaces, available at www.math.tsukuba.ac.jp/˜tasaki/akihabara/ extsym.pdf.
[3] J.-H. Eschenburg and E. Heintze: Extrinsic symmetric spaces and orbits of s-representations, Manuscripta Math. 88 (1995), 517–524.
[4] J.-H. Eschenburg, P. Quast and M.S. Tanaka: Isometries of extrinsic symmetric spaces, Asian J. of Math. 23 (2019), 439–454.
[5] D. Ferus: Immersions with parallel second fundamental form, Math. Z. 140 (1974), 87–93.
[6] D. Ferus: Symmetric submanifolds of euclidean space, Math. Ann. 247 (1980), 81–93.
[7] S. Helgason: Differential Geometry, Lie Groups, and Symmetric Spaces, Academic Press, New York- London, 1978.
[8] M. Takeuchi: Stability of certain minimal submanifolds of compact hermitian symmetric spaces, Tohoku Math. J. 36 (1984), 293–314.