Citation patterns of Korean scientists are investigated by analyzing the references of the papers authored by Korean chemists and published in two journals of different standing. Particular interest is given to how frequently Korean researchers quote the papers written by other Korean researchers and whether there is any difference in the citation pattern when Korean researchers publish their papers in a top international journal or in a domestic journal. Two journals in the category of multidisciplinary chemistry, the Journal of the American Chemical Society and the Bulletin of the Korean Chemical Society, are chosen and a detailed analysis of the references of the papers written by Korean authors in 2015 was performed. The author self-citation rate is found to be much larger than the citation rate of other Korean authors. It is also found that the percentage of self-citations and the percentage of the references by Korean authors excluding self-citations are both significantly larger in the Bulletin of the Korean Chemical Society than in the Journal of the American Chemical Society. Interpretations of the results based on social exchange theory are proposed.