1. Agricola, I., Friedrich, Th: On the holonomy of connections with skew-symmetric torsion. Math. Ann. 328(4), 711–748 (2004)
2. Akahori, T.: A new approach to the local embedding theorem of CR-structures for
$$n\ge 4$$
n
≥
4
. Mem. Amer. Math. Soc. 67(366), xvi+257 (1987)
3. Bär, Ch.: Real Killing spinors and holonomy. Comm. Math. Phys. 154(3), 509–521 (1993)
4. Boutet de Monvel, L.: Intégration des équations de Cauchy-Riemann induites formelles, Séminaire Goulaouic-Lions-Schwartz 1974-1975; Équations aux derivées partielles linéaires et non linéaires, Centre Math., Exp. No. 9, p. 14. École Polytech., Paris, (1975) (in French)
5. Baum, H., Friedrich, Th., Grunewald, R., Kath, I.: Twistor and Killing spinors on Riemannian manifolds. Seminarberichte, 108. p. 179. Humboldt Universität, Sektion Mathematik, Berlin (1990)