Upscale wrote:

Other alternatives are to clamp square blocks at the 90°
junction of a shelf and a side. A more exotic method (and more
expensive is to use something like these:
http://www.leevalley.com/wood/page.a...01&cat=1,43838

Awhile back somebody recommended looking for the guy who makes those at the
woodworking show, which I did, got a great deal. Also got a good deal on
some Bessey clamps. The 'wife gets in free' ticket even allowed me to claim
I'd provided an afternoon's free entertainment for the Mrs., score all
around.