Whitepaper from 2002 that has been updated regarding the abuse of non-HTTP protocols to launch cross site scripting attacks.
You can download it from the following link: https://packetstormsecurity.com/files/download/67441/the-extended-html-form-attack-revisited.pdf
Source: https://packetstormsecurity.com/files/67441/the-extended-html-form-attack-revisited.pdf.html