D83, D91, J16, J29, O53, Z12, Z13
C93, J16, O33, K42
(Consumer Economics: Empirical Analysis), Q42 (Alternative Energy Sources)
J24, O33, D91, J22
J22, I12, Q54
E31, C83, D84, J22
E31, C83, D84, J22, J24
I14, I15, I31, J16, J13
C91, D01, J22
O12, J22, J46, C93, I31