O13, Q13, L15, D82, C93
C93, D23, L14, M14, Q56
C93, I23
C93, D83, I21, I24
C93, D83, I21, I24, O15
C93, B55, J71
C93, D83, D91, J24, M51, O15
(Technological Change: Choices and Consequences; Diffusion Processes)
O12, Q54, I25, c93
I25, J13, D15, C93