add tooltips for the biblio buttons
add tooltips for the biblio buttons

mlda065/gummi,turbopobre/gummi,alexandervdm/gummi,turbopobre/gummi,bobi32/gummi,bobi32/gummi,alexandervdm/gummi,bobi32/gummi,mlda065/gummi,mlda065/gummi,alexandervdm/gummi,bobi32/gummi,turbopobre/gummi,turbopobre/gummi,mlda065/gummi