Apostolic Authority?

What is apostolic authority, and how did it function among early Christians? The reason for this complex question is more than just mere curiosity.

In James, those who are sick are instructed to call the elders of the church for prayer and anointing (Jas 5:14). This instruction assumes the appointment of elders, but it says nothing else about their duties or position beyond this basic description of their pastoral care for the sick. James discourages the ambition to be a teacher on the grounds that teachers will be judged with greater strictness (Jas 3:1).

But who is James to a) write this letter to a group of churches, and b) why should these communities listen to him? Did these communities have to obey? What were the boundaries of their relationship? I realise this is almost impossible to answer due to the limited evidence, so if there is someone brave enough out there who can attempt to answer this from Paul, I'd be very interested in your response.

Does anybody know of any research on apostolic authority and how it functioned amongst early Christianity? I'm not looking for a study of elders and deacons, but rather apostolic authority. For example, what gave Paul the right to write to the Colossians [assuming that Paul wrote that letter]? Paul had not planted the church in Colossae, yet still felt compelled and able to write to them and instruct them in the faith. What would of happened if they refused? The same question can easily be applied to the Corinthian situation. What if those in Corinth said "NO" to Paul. Would they have been expelled from the wider Christian community? Would the elders have been replaced [assuming there were elders at Corinth]?

To make it even easier, are there any studies on "being an apsotle"? I know of C. K. Barrett's classic study: The Signs of an Apostle. But are there others? Any that you have read and found helpful? Perhaps a PhD for/from some poor soul?

Thanks for any help...