 ተመልከት Seltzer and Anderson (2008) እያንዳንዱ ጉዳይ እና እንዲካተት መስፈርት በተመለከተ ተጨማሪ መረጃ ለማግኘት.
See Spilimbergo and others (2008) for further details on the design of appropriate policies that address sustainability concerns.