The title of the papal bull has to be read as : Quum memoranda - breve
For the full text in Italian : see this link
or even better
breve comes from brevis = short, brief
memoranda comes from memorandum = document
quum - my knowledge of Latin is already very short (I learned it more than 40 years ago in my youth - should ask it now to a catholic priest)
A lot of papal bulls begin with Quum.
Maybe this helps already a little bit