f7723559_CSS_HTML_XHTML_Reference_Book__Description_and_notes
[Property/Values] border-top, border-right, border-bottom, border-left any combination of a single value each for border-width, border-style, and/or a color, or use inherit. [Description and notes] 
for defining all three border properties at once on only one side of an element initial value depends on individual values; not inherited
CSS HTML XHTML Reference Book
Description and notes