1. The observational literature on the solar magnetic field is immense, and many good review papers are available. One I particularly like is Solanki, S. K., Inhester, B., & Schüssler, M.: 2006, The solar magnetic field, Rep. Prog. Phys., 69, 563–668
2. Hale’s original papers on sunspots are still well worth reading. The two key papers are: Hale, G. E.: 1908, On the probable existence of a magnetic field in sun-spots, Astrophys. J., 28, 315–343
3. Hale, G. E, Ellerman, F., Nicholson, S.B., & Joy, A.H.: 1919, The magnetic polarity of sun-spots, Astrophys. J., 49, 153–178
4. The study of rising toroidal flux ropes, a proxy for the emergence of the solar internal toroidal field in the form of sunspot pairs, is a topic that has generated a voluminous literature. Among the many noteworthy contributions in this field, the following are recommended as starting points: Moreno-Insertis, F.: 1986, Nonlinear time-evolution of kink-unstable magnetic flux tubes in the convective zone of the sun. Astron. & Astrophys. 166, 291–305
5. Choudhuri, A. R., & Gilman, P. A.: 1987, The influence of the Coriolis force on flux tubes rising through the solar convection zone, Astrophys. J., 316, 788–800