Abundances of lithium, carbon, nitrogen, and the carbon isotopic ratio as a function of the effective temperature for the objects listed in Table 2. A conservative error bar of 0.2 dex was adopted for the NLTE lithium shown in the upper panels. The tracks are for standard (left column) and rotating models (right column) with masses ranging from 3.0 to 4.5 M_⊙ (from left to right). The colours of the tracks indicate the evolutionary phase: black for main sequence, green for RGB, blue for central He burning and red for AGB phase. Squares in different shades of blue are used in the upper panel to represent those stars for which [C/H] and [N/H] is also available from the literature (see text). In the lower panels, the thick black line at ¹²C/¹³C = 4 represents the carbon isotopic ratio found in HD 16634 (Sneden et al. 1978) and in HD 166208 (Day 1980). The grey areas in the left column plots show the region occupied by tracks for rotating models with υ_ZAMS = 50 km s^-1 (see text).