%A Porat, Marc Uri %A United States. Dept. of Commerce. Office of Telecommunications %A National Science Foundation (U.S.) %T Definition and measurement %I U.S. Dept. of Commerce, Office of Telecommunications,For sale by the Supt. of Docs., U.S. Govt. Print. Off. %D 1977 %S OT special publication %V 77-12(1) . The information economy %U https://ci.nii.ac.jp/ncid/BA35714040