Comparison of our [O₆₁₅₈/Fe] vs. [Fe/H] trends to those derived by Ramírez et al. (2013), Bensby et al. (2014) and Nissen et al. (2014). For comparison purposes, abundance values from Ramírez et al. (2013) and Nissen et al. (2014) have been rescaled to the same solar reference (log ϵ(O)_⊙ = 8.71). Bensby et al. (2014) performed a normalization relative to their solar values on a line-by-line basis. However, individual line abundances are not provided, which makes not possible to rescale to the same solar reference.