Contingent resources are defined by the SPE-PRMS as those quantities of petroleum estimated, as of a given date, to be potentially recoverable from known accumulations by application of development projects not currently considered to be commercially recoverable due to one or more contingencies. For the audit of oil and gas reserves as of 31 December 2020 in accordance with the SPE-PRMS standards forecast (in the range between US$37 and US$78 per barrel) and not constant prices for crude oil were used. In the Company s opinion, the use of forecast prices allows to evaluate commercially recoverable reserves for the purposes of implementation of Tatneft Group Strategy more accurately. The use of constant prices, especially based on the results of such crisis year as 2020 was, does not reflect the potential of development of the Company s oilfields considering the recovery of oil markets as well projected future demand and su