Source: 2002 annual letter to Berkshire shareholders, according to http://research.lifeboat.com/buffett_warns.htm and http://www.insurancejournal.com/magazines/southcentral/2002/03/25/editorsnote/19139.htm
The 2002 letter can be found here:
http://www.berkshirehathaway.com/letters/2002pdf.pdf
Source: 2002 annual letter to Berkshire shareholders, according to http://research.lifeboat.com/buffett_warns.htm and http://www.insurancejournal.com/magazines/southcentral/2002/03/25/editorsnote/19139.htm
The 2002 letter can be found here:
http://www.berkshirehathaway.com/letters/2002pdf.pdf