Research progress of contingent valuation method for application to agricultural ecological compensation Contingent valuation of the existent economic of Giant Panda (Ailuropoda melanoleuca) Evaluation on non-use values of typical lake wetlands in Wuhan Improving validity and reliability of contingent valuation method through reducing biases and errors: theory, method and application Using CVM to estimate the restoring cost of Maqu grassland nfluencing factors analysis of willingness to pay for ecosystem services evaluation of Hongze Lake The assessment of non-market value of agricultural land resource in Wuhan