Like the other CJK characters, they are listed by KangXi radical order, although some of the characters may not be found in the Kangxi Dictionary (康煕字典)
Historically, the area now occupied by the CJK UI Extention A was once taken up by Korean Hangeul. There are 6852 characters now encoded in CJK UI Ext-A. It first appears in Unicode 3.0 (published in 2000), and users may find it hard to find fonts which contain this list of characters.
Therefore, this section has been separated from the main body of CJK characters which are visible with current fonts. Since there are considerably fewer characters, several radicals will be grouped together in one page, but separated so that each radical has it's own listing. Not every one of the 214 radicals may have entries in CJK Unified Ideographs Extention A
The new MS Office 2000 compatible font called Arial Unicode MS Font contains all the characters in Unicode 2.1. From their webpage
"The font Arial Unicode MS is a full Unicode font, containing all of the approximately 40,000 alphabetical characters, ideographic characters, and symbols defined in the Unicode 2.1 standard. Because of its considerable size and the typographic compromises required to make such a font, Arial Unicode MS should be used only when you can't use multiple fonts tuned for different writing systems."
Extention A was brought in only in Unicode 3.0 (in year 2000), therefore, Extention A characters ARE NOT visible using this font.
I do not know of an additional font which may be downloaded to view these characters. The character lists appearing in this section are for future Extention A compatible software for the time being.
Saturday 30 December 2000