TY  - JOUR
AU  - Jaffe,Adam B.
AU  - Trajtenberg,Manuel
TI  - International Knowledge Flows: Evidence from Patent Citations
JF  - National Bureau of Economic Research Working Paper Series
VL  - No. 6507
PY  - 1998
Y2  - April 1998
UR  - http://www.nber.org/papers/w6507
L1  - http://www.nber.org/papers/w6507.pdf
N1  - Author contact info:
Adam B. Jaffe
MS 021
Brandeis University
Waltham, MA 02454
Tel: 781/736-3451
Fax: 781/736-3457
E-Mail: ajaffe@brandeis.edu

Manuel Trajtenberg
Eitan Berglas School of Economics
Tel-Aviv University
Tel-Aviv 69978
ISRAEL
Tel: 972-3-640-9911
Fax: 972-3-640-9908
E-Mail: manuel@post.tau.ac.il
AB  - This paper explores the patterns of citations among patents taken out by inventors in the U.S., the U.K., France, Germany and Japan.  We find (1) patents assigned to the same firm are more likely to cite each other, and come sooner than other citations; (2) patents in the same patent class are approximately 100 times as likely to cite each other as patents from different patent classes there is not a strong time pattern to this effect; (3) patents whose inventors reside in the same country are typically 30 to 80% more likely to cite each other than inventors from other countries, and these citations come sooner; and (4) there are clear country-specific citation tendencies; e.g., Japanese citations typically come sooner than those of other countries.
ER  -