http://www.mindat.org/u-3423.html The mindat.org user blog written by David Aldridge http://www.mindat.org/article.php/106/Swap+List+For+David+Aldridge Wed, 12 Dec 2007 Published: Wed, 12 Dec 2007, Subject: Swap List For David Aldridge http://www.mindat.org/article.php/36/The+Extraction+Of+Arsenic+From+Realgar Sun, 14 Oct 2007 Published: Sun, 14 Oct 2007, Subject: The Extraction Of Arsenic From Realgar