1. Bourgain, J.: Some remarks on Banach spaces in which martingale difference sequences are unconditional. Ark. Mat. 21, 163–168 (1983)
2. Burkholder, D.L.: A geometric condition that implies the existence of certain singular integrals of Banach-space-valued functions, 1983, Conference on harmonic analysis in honor of Antoni Zygmund, Vol. I, II (Chicago, Ill., 1981), Wadsworth Math. Ser., Wadsworth, Belmont, CA, 270–286
3. Coifman, R.R., Meyer, Y.: Au delà des opérateurs pseudo-différentiels Astérisque. Société Mathématique de France, Paris (1978)
4. Culiuc, A., Di Plinio, F., Ou, Y.: Domination of multilinear singular integrals by positive sparse forms. J. Lond. Math. Soc. 98(2), 369–392 (2018). https://doi.org/10.1112/jlms.12139
5. David, G., Journé, J.-L.: A boundedness criterion for generalized Calderón–Zygmund operators. Ann. Math. (2) 120, 371–397 (1984). https://doi.org/10.2307/2006946