00257nam a2200109 a 450000500170000002000150001708200190003210000160005124500230006726000390009030000180012920251203090514.0  a0713134941  a333.7,bD, nor  aNorton, G.A  aResource economics  aLoNew DelhionbEdward Arnoldc1984  avi,164p, 22cm