1. The Cost-effectiveness of Federal Tax Subsidies for Petroleum Reserves: Some Empirical Results and Their Implications;See James;STUDIES IN ENERGY TAX POLICY
2. These tax subsidies [percentage depletion allowance and expensing of intangible drilling costs] led to increased capital flows into exploration;J Walter;AM. ECON. REV,1979
3. The depletion allowance is primarily an ad valorem subsidy to mineral rights owners;, Paul See;AM. ECON. REV,1964