Perfurador de cartão (Portuguese Wikipedia)

Analysis of information sources in references of the Wikipedia article "Perfurador de cartão" in Portuguese language version.

refsWebsite

Global rank Portuguese rank

1books.google.com

3^rd place

6^th place

1,131^st place

921^st place

books.google.com

Business automation, Volume 19, Hitchcock Pub. Co., 1972 p.38

ibm.com

www-03.ibm.com

IBM Archive: Keypunch operators, 1934, Stockholm