EthernetClient.h questions:

The following is taken from the said file from IDE 1.0.5 r2:

#include "Arduino.h"	
#include "Print.h"
#include "Client.h"
#include "IPAddress.h"

My question is why the double quotation instead of brackets?

I'm writing my own xbee_wifi_client class and want to borrow what Arduino team did. Just curious.

Another question:

  using Print::write;

What does it do exactly?