1. Ablowitz, M.J., Fokas, A.S.: Complex Variables, Introduction and Applications. Cambridge University Press, Cambridge (1997)
2. Ambartsumian, V.A.: Light scattering by planetary atmospheres. Astron. Zhurnal 19, 30–41 (1942)
3. Bothner, T.: On the origins of Riemann–Hilbert problems in mathematics. Nonlinearity 34, R1–R73 (2021)
4. Busbridge, I.W.: The Mathematics of Radiative Transfer. Cambridge University Press, London (1960)
5. Carleman, T.: Sur la résolution de certaines équations intégrales. Ark. Mat. Astr. Fys. 16, 1–19 (1922)