My question involves a marriage in the state of: California

Hi,

I'm trying to write a motion to terminate spousal support (not child support, we don't have children).
For it, I need to quote the relevant family code laws. My marriage was 7 years, so the support period should be 3.5 years as far as I have read, but there is no law that specifies this (checking the California Family Code). When citing it, what is it called? Is it precedent or what?
It might not fly well if I mention that "everybody on the web says that it is half the time of the marriage." If it is precendent, where is that one? I assume that there was one landmark case which formed the precedent. How can I find out about it?

Thanks