seeking source files for HPLIP package documentation

Where do I find the source files for the hplip package man-pages and other documentation files?

I found where I might download the hplip tar-ball. After extracting the contents, I did not find the man-page "source" files.
Using synaptic, I found several "hplip*" packages but "sudo apt-get source {package}" did not find any files for download.

For example:
==========
prompt$ sudo apt-cache search hplip

hplip - HP Linux Printing and Imaging System (HPLIP)
hplip-data - HP Linux Printing and Imaging - data files
hplip-dbg - HP Linux Printing and Imaging - debugging information
hplip-doc - HP Linux Printing and Imaging - documentation
...
hplip-gui - HP Linux Printing and Imaging - GUI utilities (Qt-based)

prompt$ sudo apt-get source hplip-doc

Reading package lists... Done
Building dependency tree
Reading state information... Done
Picking 'hplip' as source package instead of 'hplip-doc'
E: Unable to find a source package for hplip
==========