Most of the icons were derived from the following SVG's placed into the public domain in openclipart:
Derived from those designed by Architetto Francesco Rollandin:
install: computer/buttons/tasto_2_architetto_franc_01 installBox: computer/buttons/tasto_2_architetto_franc_01 remove: computer/buttons/tasto_8_architetto_franc_01 removeBox: computer/buttons/tasto_8_architetto_franc_01 out-of-date: computer/buttons/tasto_10_architetto_fran_01 up-to-date: computer/buttons/tasto_10_architetto_fran_01 check: computer/buttons/tasto_7_architetto_franc_01
Derived from one designed by Juliane Krug:
package: containers/box_juliane_krug_s suite: containers/box_juliane_krug_s group: containers/box_juliane_krug_s
Inkscape was used to edit all the above into their current forms, and to create the SVG images. It also was used to resize all SVG's to around 108.6pts.