Part,  Chapter, Paragraph

1   II,     5.  5.  3|     smoking, or may reflect confounding or behaviour associated
2  III,    10.  1.  1|    pathway between the two. Confounding is a threat to validity
3  III,    10.  1.  3|  113:13-22.~Szklo M (2000): Confounding and interaction. Arch Dermatol
4  III,    10.  5.  2|   existing national studies confounding factors such as age distribution
5   IV,    11.  6.  4| assess the influence of the confounding factors (e.g. the specific