These are a series of technical field reports on issues with tile installations
http://www.ctioa.org/index.cfm?pi=FR
These are more specifc in relation to floors
http://www.ctioa.org/index.cfm?pi=FSI
It a little techincal but the Ceramic Tile Institue has had a long history of helping the industry with good info.
Check it out...
Mark Lauzon
www.stoneadvice.com
slab fabricator heaven