Analysis of information sources in references of the Wikipedia article "Proven reserves" in English language version.
The new Russian Federation classification system for petroleum reserves (RF-2013) has introduced the concept of economic limits. The system, which was approved in November 2013 by the Ministry of Natural Resources, will go into effect Jan. 1, 2016. [..] In the new system, discovered fields are classified into two major groups—Fields under Exploration and Fields under Development according to maturity level.