http://www.erowid.org/library/books_online/pihkal/pihkal036.shtml (http://www.erowid.org/library/books_online/pihkal/pihkal036.shtml)
http://www.erowid.org/library/books_online/pihkal/pihkal043.shtml (http://www.erowid.org/library/books_online/pihkal/pihkal043.shtml)