1. Adler, A. (1928). Characteristics of the first, second and third child. Children, 3, 14–52.
2. Adler, A. (2008). Menschenkenntnis. Köln: Anaconda.
3. Bohnsack, R. (2014). Rekonstruktive Sozialforschung. Einführung in qualitative Methoden (9., überarb. u. erw. Aufl.). Opladen/Toronto: Barbara Budrich.
4. Boll, T., Ferring, D., & Filipp, S.-H. (2003). Perceived parental differential treatment in middle adulthood: Curvilinear relations with individuals’ experienced relationship quality to sibling and parents. Journal of Family Psychology, 17(4), 472–487.
5. Bollmann, V. (2012). Schwestern. Interaktion und Ambivalenz in lebenslangen Beziehungen. Wiesbaden: Springer VS.