One way to increase the quality of the literature that you integrate in a scientific manuscript is by a search that is based on the Author of a relevant article.  For instance search the Web of Science for information on other papers published by Aldo Leopold.  Another incredibly neat way to search is by searching to see who has cited Aldo Leopold in their publications recently--these new papers may be a great addition to your manuscript.  In this manner, information on the topic of interest can then be integrated into your paper.