Left panel: the spectral region around the Ca, Fe, Ba, and Y absorption lines for the 12 stars in Draco. Although the Ca and Fe lines are quite similar, the strengths of the Ba and Y lines differ markedly for the eight objects at the top vs. the other four objects. Right panel: the absorption lines of Fe I 6358 Å, Ba II 5854 Å, Y II 4884 Å, and Eu II 6645 Å of Irwin 20751 (left panels) and SDSS J171627+574808 (right panels). The two stars have similar stellar parameters but show the different Ba, Y, and Eu abundances. The observed spectra indicated by black points are compared with the best-fit results (red solid lines), together with the synthesized spectra with Δ[X/H] = ± 0.3 dex offsets (X = Fe, Ba, Y, Eu; blue dashed lines). The red dashed line for Eu in Irwin 20751 shows a synthetic spectrum to determine the upper limit of Eu abundance.