1. Cameron, R.H. and Schüssler, M., The turbulent diffusion of toroidal magnetic flux as inferred from properties of the sunspot butterfly diagram, Astron. Astrophys., 2016, vol. 591, p. A46.
2. Clette, F., Svalgaard, L., Vaquero, J.M., and Cliver, E.W., Revisiting the sunspot number: A 400-year perspective on the solar cycle, Space. Sci. Rev., 2014, vol. 186, pp. 35–103. http://www.sidc.be/silso/datafiles.
3. Du, Z.L., The shape of solar cycle described by a modified Gaussian function, Sol. Phys., 2011, vol. 273, pp. 231–253.
4. Eigenson, M.S. and Gnevyshev, M.N., Ohl, A.I., and Rubashev, V.M., Solnechnaya aktivnost' i ee zemnye proyavleniya (Solar Activity and Its Terrestrial Manifestations), Moscow–Leningrad: OGIZ, 1948.
5. Gnevyshev, M.N. and Gnevysheva, R.S., Relationship between the Schwabe–Wolf and Spörer laws, Byull. Kom. Issled. Solntsa, 1949, no. 1, pp. 1–8.