[El/Fe] ratio as a function of [Fe/H] in the investigated stars of Group 2 (filled circles) and comparison stars analysed in this work and Paper II (open circles). The data for the Milky Way thin-disc dwarfs were taken from Edvardsson et al. (1993, plus signs), Gratton & Sneden (1994, triangles), Koch & Edvardsson (2002, upside down triangles), Bensby et al. (2005, stars), Reddy et al. (2006, 2003, squares), Brewer & Carney (2006, diamonds), Mashonkina et al. (2007, crosses), and Mishenina et al. (2013, dots). The Galactic thin-disc chemical evolution model is shown as a solid line (Pagel & Tautvaišienė, 1997). Average uncertainties are shown in the box for Zr.