Natural logarithm of the ratio of the line strength S in the Babushkin form to the line strength S in the Coulomb form, as a function of the G_{S = 0} parameter inthe range where ln(S_B∕S_C) reflects the real accuracy of the calculation (right part of Fig. 26 a). The limits of the accuracy classes are marked in different colors. The red lines correspond to the AA accuracy class limit, and the green ones correspond to the A+ accuracy class limit. The other limits of the accuracy classes are also marked.