Non paywall link: http://www.wsj.com/articles/payments-startup-square-files-confidential-ipo-1437782181 http://www.wsj.com/articles/payments-startup-square-fil

Non paywall link: http://www.wsj.com/articles/payments-startup-square-files-confidential-ipo-1437782181 http://www.wsj.com/articles/payments-startup-square-files-co...