You can browse all the published concept maps without signing in. If you'd like to create your own concept maps, all you have to do is sign in with Twitter. It's free!
(ODV) This is a set of rules, rather than a valuation approach, which describe the value boundaries for specified assets employed in monopoly markets. The rules are a combination of a cost based approach (ODRC) and the economic value where the ODV is taken to be the lowest of these.
IIMM