In some circumstances you may have to quote from an indirect source. An indirect source is a source cited in another source. For such indirect quotations, use "qtd. in" to indicate the source you actually consulted.
Ravitch argues that high schools are pressured to act as "social service centers, and they don't do that well" (qtd. in Weisman 259).
A responsible research will try to locate the original source.
The reference librarians will be happy to assist you in finding the source.
Taken from the Purdue Owl