Hyogo Prefecture air-defense Order No. 570 on matters pertaining to the use of sirens for the transmission of security warning and all-clear signals (Japanese). Report No. 7hhh, USSBS Index Section 2

Text on matters pertaining to the revision of methods of signaling to ships with air warning signal lights (Japanese). Report No. 4ww, USSBS Index Section 2

Manual issued by the defense section of the Hyogo prefectural police division giving instructions for the care and use of sirens (Japanese). Report No. 7h, USSBS Index Section 2