Location of the kernel source files in FC-4

I am forced to use FC-4 in my work-place. I am not able to find the kernel source files on my comp. The location /usr/src contains the following directories : debug kernels redhat
Where exactly are the source files stored Or does it mean, the source files are just not installed on this comp?

I think that just means the source tree isn't installed.

Sorted that out. The source was in the kernels directory. Thanks