object copy with reference

Hello,

I need a tip / hint for solving the following problem:

I have a class method that is run in different threads:
myclass::mythreadmethod( mysuperclass& )

mysuperclass is a reference variable, that is used during the thread is
running.
Anyway the method should be myclass::mythreadmethod( mysuperclass ), so that
each running thread has a own local copy of the object, but I can't
switch the parameter
because the method is derivated of another class.

I need in the method a local (deep-copy) of my object. So I create a
clone method like
myclass::mythreadmethod( mysuperclass& pobj )
{
    mysuperclass& lobj = p_obj.clone();
}

In this case I get the compiler error, that I try to set up a temporary
assignment.

The try to do it like
myclass::mythreadmethod( mysuperclass& pobj )
{
    mysuperclass& lobj;
   p_obj.clone(lobj);
}
create the message l_obj isn't initializate.

Does anyone has some tips to create a working solution? The perfect solution
should be a deep-copy of the pobj reference

Thanks

Phil