A citation identifies a book, periodical article, or other information resource. It includes the basic information someone would need to find the item, and is used to create the list of references or bibliography in a research paper.
Enhao, G., Xiaoyun, W., & Rongsha, L. (2011). A Half-Blood Half-Pipe, A Perfect Performance. UMAP Journal, 32(2), 109-122.
An abstract is a brief summary of a book, periodical, or other resource.
"The article presents a study of a half-pipe which is a venue for extreme sports including snowboarding and skateboarding. It provides an overview on the concave ramps of a half-pipe which are topped by copings and decks including a transition and a vert. It also mentions the different terminology and definitions used in the study which include cycle, flight, and flight distance."
The full-text is the full book or article. This usually refers to the online version of a book or article.