If a statement made in an answer is derived from a particular source, the link between the statement and the source should be made clear. For example,
- If the statement is a direct quote, then it should be in quotation marks or use the indented quotation markup feature.
- If the statement summarises the ideas of another source, then statements like "Author X suggests" or "Author X states" or "Author X found", are good strategies, etc.
Of course, there are many ways of communicating the link between statement and source. The important point is that the writing communicate this link.
Perhaps some notes I wrote a while back on how to write a literature review are of some relevance.
Making the link clear: Good literature reviews clearly communicate the
relationship between a statement and an accompanying citation. Is the
citation a baseless assertion, an established theory, or an empirical
finding? The following examples tend to be superior to ending a
sentence with a mystery citation: “A study by Smith showed”, “Smith
has suggested that”, “Smith has theorised”, “Smith obtained results
supporting the idea that”. Good literature reviews give a sense of the
strength and nature of the evidence provided by the citation. Putting
an author’s name at the end of a sentence tends to not fulfil this
need. Thus, the words around the citation can explain the reasons why
the author asserted the idea in the first place. Did the author base
the claim on common sense? Was it an empirical finding? Was it based
on the summary of a set of empirical results or meta-analysis?
For example: Poor: “Perceptual speed, psychomotor and general
abilities relate to the three phases of skill acquisition in different
ways (Ackerman, 1988).” Better: “Ackerman (1988) has theorised that
perceptual speed, psychomotor and general abilities relate to skill
acquisition phases in different ways.” Even Better: “Ackerman (1988)
performed a series of large sample empirical studies using a range of
simple psychomotor tasks which provided partial support for his theory
that perceptual speed, psychomotor and general abilities relate to
skill acquisition phases in different ways.”