You are referring to secondary citing, meaning that you are quoting a source that was mentioned in an article/book that you read, but are not using the text of the work beyond what you found quoted. The article/book that you read is the secondary source, and the information you are quoting is from the original source.
MLA Example:
In MLA style, citations taken from a secondary source should generally be avoided; consult the original work whenever possible. If only an indirect source is available, put the abbreviation qtd. in (quoted in) before the indirect source in the parenthetical reference and include the indirect (secondary) source in the Works Cited. (MLA Style, sec. 6.4.7)
parenthetical reference in MLA Style
In a May 1800 letter to Watt, Creighton wrote, "The excellent Satanism reflects immortal honour on the Club" (qtd. in Hunt and Jacob 493).
works cited list in MLA Style
APA Example:
In APA Style, citations taken from a secondary source should be used sparingly. For example, you can use them when the original work is out of print, unavailable through usual sources, or not available in English. Cite the secondary source in the reference list or bibliography; in the text, name the original work and cite it using the secondary source. (from http://www.apastyle.org/learn/faqs/cite-another-source.aspx)
parenthetical reference in APA Style
Goldman and Goldman's study (as cited in Linebarger, 2001) found ....
reference list in APA Style
Linebarger, D. L. (2001). Learning to read from television: The effects of using captions and narration. Journal of Educational Psychology, 93(2), 288-298.
APA citation examples from http://library.williams.edu/citing/styles/apa.php
