Prof. M. Kobayashi - Prof. T. Maskawa's Novel Prize Winning Paper was published by SPARC Japan partner journal Progress of Theoretical Physics and has been freely available on their website.

Progress of Theoretical Physics
Vol. 49 No. 2 (1973) pp. 652-657

URL : http://ptp.ipap.jp/link?PTP/49/652/
DOI : 10.1143/PTP.49.652

CP-Violation in the Renormalizable Theory of Weak Interaction

Makoto Kobayashi and Toshihide Maskawa
Department of Physics, Kyoto University, Kyoto

The American Physical Society also announced that three of Professor Nambu's articles describing work honored by his Nobel Prize had been made free-to-read. Links to the articles follow:

http://prola.aps.org/abstract/PRL/v4/i7/p380_1
http://prola.aps.org/abstract/PR/v122/i1/p345_1
http://prola.aps.org/abstract/PR/v124/i1/p246_1