Problem headers mail php

I sending a message with this code below and works:

$headers = 'From: Online <'.$emailT开发者_如何学编程o.'>\r\n'; 
$headers .= 'Reply-To: '.$emailTo.'\r\n';
$headers .= 'Return-Path: Online <'.$emailTo.'>\r\n';
$headers .= "Bcc: email@hotmail.com\r\n";
$headers .= "Bcc: email@gmail.com\r\n";

The problem is When I click in Reply on the email appear like this in the field to:

Online \r\nReply-To: email@server.com.au\r\nReturn-Path: Online \r\nBcc: email@hotmail.com

Any idea that can help me? Cheers M

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\r and \n must be enclosed in double quotes, in single quoted strings they are taken literally.