In this study, it was investigated if there were some differences on the preference of researchers to grey literature among seven different subjects in the field of science and technology using citation analysis. The result shows that there were some differences among researchers, depending on the subject area. It also appears that the preference of grey literature of researchers is dissimilar in journals in English and journals in Korean, regardless of the subject area. Finally, partial correlation coefficient among nine different types of material was counted with the control of languages used and subject areas included. Among nine types of cited documents, the value of partial correlation coefficient between proceedings and miscellaneous is larger than that of any other coupled comparison This means that researchers who cite articles from proceedings tend to include information from miscellaneous at the same time.