[Ba/Fe] vs. [Eu/Fe] in carbon-normal and carbon-rich metal-poor stars (blue dots and red crosses, respectively). Stars enriched in s-elements occupy the region above the horizontal and diagonal solid black lines, corresponding to zones A and B of the plot. According to our adopted definitions, CEMP-r/s stars are in zone B. In zone C there are stars with [Ba/Fe] > 1, [Eu/Fe] > 1, and [Ba/Eu] < 0. CEMP-r stars and carbon-normal stars with [Eu /Fe] > 1 and [Ba/Fe] ≤ 1 are in zone D. The dashed-blue and solid-magenta lines are linear fits of the carbon-normal stars and CEMP-s stars, respectively. The red and blue distributions represent the results of our theoretical model for CEMP and carbon-normal metal-poor stars.