Where can I obtain the GN 364

GN should stand for Gazette notice, Hong Kong government issues a lot of GN so there are thousands of them.
GN364 is related to the plot ratio of lands in New Terrorities. In most simple terms, leases under GN364 allow the leasees to use 2/3 of the site area to build a 2-storey residential building.
The other popular GN related to leases is GN365.
Unfortunately, it seems that gazette notices are not available for downloading and you have to go to the Lands Department.

2008-03-28 22:23:55 補充：
GN 364 of 1934: no restriction on user, but 66% site coverage, max. limit 2-storeys

GN 365 of 1906: no restriction on user / site coverage, only a 2-storey height control and 24-month building covenant period

Only the Government notices or Gazetteed notices after 2000 are available for downloading.