The main reference book in English is 'Aircraft Instruments' by Pallet which is used by the CAA to reference questions about gyros, compasses and basic flight instruments. Autoflight is referenced partly to this book and partly to the B737-400 Technical Manual. FMS is B737-400, other systems such as altitude alert, TCAS etc can be either Boeing or Airbus but predominantly Boeing with some questions only answerable from the Maintenance Manuals. The questions about tachometers, ratiometers and fuel flow meters appear to originate from the Dutch ATPL syllabus of the 1990's and the best references I can find are ATPL notes from that period. Hope this helps, Pallet is heavy going!