When you click on links to various merchants on this site and make a purchase, this can result in this site earning a commission. Affiliate programs and affiliations include, but are not limited to, the eBay Partner Network.
And to what, exactly, does the concept of validity apply?. How many different kinds of validity are there?When does validation begin and end?Is reliability a part of validity, or distinct from it?. Author Paul E. Newton, Stuart D. Shaw.
When you click on links to various merchants on this site and make a purchase, this can result in this site earning a commission. Affiliate programs and affiliations include, but are not limited to, the eBay Partner Network.