Using the following code I am able to get the logs of calls and SMS’s. How do I modify this code to only search between certain dates using PHP?

// Instantiate a new Twilio Rest Client 
$client = new Services_Twilio($AccountSid, $AuthToken, $ApiVersion); 

// http://www.twilio.com/docs/quickstart... 
try { 
  // Get Recent Calls 
  foreach ($client->account->calls as $call) { 
    echo "Call from $call->sid : $call->from to $call->to at $call->start_time of length $call->duration $call->price <br>"; 
  } 
} 
catch (Exception $e) { 
  echo 'Error: ' . $e->getMessage(); 
} 

Best regards

Andre