"In 2004 Janet Yellen Feared Housing Bust But Did Not Raise Public Alarm" by Marilyn W. Thompson, Ann Saphir, and Alister Bull, www.businessinsider.com. October 30, 2013.
"'Over the different views with regard to the actual infinite numbers' ('Ueber die verschiedenen Ansichten in Bezug auf die actualunendlichen Zahlen')". Book by Georg Cantor, 1886.