The first time I ever learned about differences in the primary, secondary or tertiary sources of literature was in one of my second year Biology course. Primary and secondary sources can easily be found online but some reliable databases to find them are PubMed, Google scholar, Annual Review of Ecology, Evolution, and Systematics etc
Primary sources of literature provide first hand evidence gathered by the author or a document relating to direct experience. In other words it’s defined as new information. Sources of primary literature in science include research articles and autobiographies. A specific example of a primary article would be “Bacillus lipopeptides as powerful pest control agents for a more sustainable and healthy agriculture: recent studies and innovations.” This article can easily be found online.
https://www.ncbi.nlm.nih.gov/pubmed/32086615
Secondary sources of literature describe, summarize, interpret or analyzes information from other sources. Sources of secondary literature in science include many books, textbooks or scholarly articles.A specific example of a secondary source would be an ecology textbook or the review article “Ecological and physiological mechanisms of growth decline of Robinia pseudoacacia plantations in the Loess Plateau of China: A review.” This review article can be found online.
https://www.ncbi.nlm.nih.gov/pubmed/30039683
Tertiary sources of literature compile and summarize primary and secondary sources. Sources of tertiary literature in science includes manuals, guide books,encyclopedias, bibliographies or handbooks.A specific example of a tertiary source would be the field guide named A Peterson Field Guide to Edible Wild Plants: Eastern and central North America by Lee Allen Peterson, Roger Tory Peterson.
Applied Plant Ecology Winter 2020 