Darwin claims or Darwin claimed?

When writers cite sources for their information the standard format is:

            Malevic (2003) claims/ states/ argues that …

using the present tense for the verbs of reference.

However, in some situations it can be more suitable to use the past tense:

             Bernstein (1978) maintained/ believed that …

 The past tense usually suggests that either:

a) The information or idea is outdated (and is contrasted with a more recent view) or
b) The author has died

However, there is no hard or fast distinction between the two tenses, and in some borderline cases either may be used.

The first time a source is cited give both first and family names:
         
         Harry Moore (1954) suggested that …

but in subsequent citations only use their family name.

 Note also that it is not normal practice to give titles eg

          Bernstein (1978) maintained that

not: Professor/ Dr Bernstein …

 For further information about Verbs in Citations see:

Academic Writing Chapter 3.14 page 236