How to link to a function read in with automodule in Sphinx

Question

I read in a module (e.g. func.py) with the automodule function in Sphinx.

func.py could look like that

def funca(arg1):
    """ Docstring funca """
    return arg1
def funcb(arg2) 
     """ Docstring funcb """
    return arg2    

I read func.py in with automodule like that.

.. automodule:: func
   :members:

At a different point in the documentation I want to include a link to for example to funca.

What is the best way of doing that? I have still some trouble understanding how the references in Sphinx work.