in-text citation question

Hi list:
I have a question about changing in-text citation (using
v9.0). Normally
we put in-text citation at the end of sentence, such as
"A is larger
than B (Smith 2003)". But sometimes I would like start
a sentence with
the citation, such as "Smith (2003) found A is larger
than B." Similar
situation that if I want to add a page number after a book
citation in
the text, such as "A is larger than C (Smith 2003:
15-17), and D is also
important (Smith 2003: 35-40)". How can I do this? I've
tried changing
it directly in the text but of course it will change back. 

Thanks in advance.
Ross