Sources for the "enhanced PC layout" with 101/102-keys featured in the IBM model M (top): the IBM 122-key terminal keyboards (right bottom) &amp; the IBM PC AT keyboard with 84-keys (left bottom). Influence color coded.
File:IBM_model_F_3887360487_ca719998f0_o.jpg / https://commons.wikimedia.org/wiki/File:102-key_Model_M.jpg / https://commons.wikimedia.org/wiki/File:AT_keyboard.jpg
https://www.flickr.com/people/moparx / https://commons.wikimedia.org/wiki/User:Berntie / https://commons.wikimedia.org/wiki/User:Jleedev