Hello Paul Eggert,
On 05/10/2014 10:22, Paul Eggert wrote:
Trần Ngọc Quân wrote:
Dr. Lê thành Lân
I find his email, but it I'm not sure he still use it. But I will try to contact.
lethanhlan@yahoo.de I will try to contact Hồ Ngọc Đức.
Unfortunately, I can't contact both of them.
We need to correct the Asia/Ho_Chi_Minh entry regardless of what we do about Hanoi, and that is what the patch does.
Of cause, Asia/Ho_Chi_Minh properly need to fix.
  As I pointed out in my most recent email, it appears to be unnecessary to add an entry for Hanoi, since Hanoi does not have a unique time zone history since 1970.  In contrast, Ho Chi Minh City (now that its data are corrected) does have a unique time zone history since 1970 and therefore needs a distinct Zone.
Wiki [1] point out Hanoi and Ho Chi Minh timezone diff from 1970 - 1975: Hanoi used GMT +7 while Ho Chi Minh used GMT +8. So I sure timezone in Hanoi is unique. You decide add or not by yourself.
I read carefully both [1] and [2]. They are the same content. I think they are the best document. So you can use [1].

Paul Eggert, please make new patch. I will review.
About Cambodia and Lao, I recommend remove them. They can use Asia/Bangkok instead. Unique timezone for them will create when we have enough document.

[1] http://en.wikipedia.org/wiki/Time_in_Vietnam
[2] http://www.thoigian.com.vn/?mPage=P80D01

-- 
Trần Ngọc Quân.