= 140 pc) molecular complexes, we used the values from the study of Hilton & Lahulla (1995) or the results of Dame et al. (1987) on the locations of the major (giant) molecular clouds in the Galaxy to give an estimate of the distances by relating the cores to known molecular complexes according to their galactic coordinates. Column 5 gives the ISOCAM filter(s) we used for the observations of each core. Column 7 lists the mean mid-IR intensity measured off the absorption features. Included in the values listed in column 7 is the zodiacal light emission (given in Column 8). Column 9 lists the relative contrast between the intensity of the main absorption feature and the mean mid-IR intensity (column 7), in percentage of the mean mid-IR intensity [^5].

Finally, column 10 gives the references of the dark cloud catalogues, from which our fields were selected, as well as the references of a few studies containing interesting information on the sources. From Table \[sources\], it can be seen that the majority of the fields we observed contain absorption features. Figure \[absorption\] shows eleven cores with deep absorption (i.e., L1544, L1582A, Oph D, R53, L1709A, R63, L1689B, L310, L328, L429, GF5 