* asia, backzone: Verify Trần 2005 and add sources.

I obtained a copy of Trần Tiến Bình's 2005 book "Lịch Việt Nam:
thế kỷ XX-XXI (1901-2100)", verified that www.thoigian.com.vn's
page is a verbatim quote of a passage in pages 45-50, and added a
list of Trần's sources for his pp 49-50.

2 files changed, 20 insertions, 11 deletions

diff --git a/asia b/asia
index 851e6f8..37b2c88 100644
--- a/asia
+++ b/asia
@@ -2774,16 +2774,14 @@ Zone	Asia/Tashkent	4:37:11 -	LMT	1924 May  2
 # The English-language name of Vietnam's most populous city is "Ho Chi Minh
 # City"; use Ho_Chi_Minh below to avoid a name of more than 14 characters.
 
-# From Paul Eggert (2014-10-04) after a heads-up from Trần Ngọc Quân:
+# From Paul Eggert (2014-10-21) after a heads-up from Trần Ngọc Quân:
+# Trần Tiến Bình's authoritative book "Lịch Việt Nam: thế kỷ XX-XXI (1901-2100)"
+# (Nhà xuất bản Văn Hoá - Thông Tin, Hanoi, 2005), pp 49-50,
+# is quoted verbatim in:
 # http://www.thoigian.com.vn/?mPage=P80D01
-# lists helpful info, translated by Brian Inglis in:
+# is translated by Brian Inglis in:
 # http://mm.icann.org/pipermail/tz/2014-October/021654.html
-# The info cites an authoritative book by Trần Tiến Bình; a 2014 edition is
-# "Lịch Việt Nam: thế kỉ XX-XXI (1901-2100) & niên biểu lịch sử Việt Nam"
-# http://bookaholic.vn/lich-viet-nam-the-ki-xx-xxi-1901-2100-va-bien-bieu-lich-su-viet-nam/
-# I have asked my library for its copy of the book (a 2005 edition)
-# and plan to check that.  In the meantime the summary in Thời gian is much
-# better than Shanks, and is the basis for the following info.
+# and is the basis for the information below.
 #
 # The 1906 transition was effective July 1 and standardized Indochina to
 # Phù Liễn Observatory, legally 104 deg. 17'17" east of Paris.
@@ -2803,6 +2801,17 @@ Zone	Asia/Tashkent	4:37:11 -	LMT	1924 May  2
 # To 07:00 on 1955-07-01 in South Vietnam.
 # To 08:00 on 1959-12-31 at 23:00 in South Vietnam.
 # To 07:00 on 1975-06-13 in South Vietnam.
+#
+# Trần cites the following sources; it's unclear which supplied the info above.
+#
+# Hoàng Xuân Hãn: "Lịch và lịch Việt Nam". Tập san Khoa học Xã hội,
+# No. 9, Paris, February 1982.
+#
+# Lê Thành Lân: "Lịch và niên biểu lịch sử hai mươi thế kỷ (0001-2010)",
+# NXB Thống kê, Hanoi, 2000.
+#
+# Lê Thành Lân: "Lịch hai thế kỷ (1802-2010) và các lịch vĩnh cửu",
+# NXB Thuận Hoá, Huế, 1995.
 
 # Zone	NAME		GMTOFF	RULES	FORMAT	[UNTIL]
 Zone Asia/Ho_Chi_Minh	7:06:40 -	LMT	1906 Jul  1
diff --git a/backzone b/backzone
index 1a7cc3e..29320aa 100644
--- a/backzone
+++ b/backzone
@@ -333,8 +333,8 @@ Link Asia/Chongqing Asia/Chungking
 # Vietnam
 # From Paul Eggert (2014-10-13):
 # See Asia/Ho_Chi_Minh for the source for this data.
-# Trần's book is quoting as saying the 1954-55 transition to 07:00
-# in Hanoi was in October 1954, with exact date and time unknown.
+# Trần's book says the 1954-55 transition to 07:00 in Hanoi was in
+# October 1954, with exact date and time unspecified.
 Zone	Asia/Hanoi	7:03:24 -	LMT	1906 Jul  1
 			7:06:30	-	PLMT	1911 May  1
 			7:00	-	ICT	1942 Dec 31 23:00
@@ -391,7 +391,7 @@ Zone	Asia/Tel_Aviv	2:19:04 -	LMT	1880
 # Laos
 # From Paul Eggert (2014-10-11):
 # See Asia/Ho_Chi_Minh for the source for most of this data.
-# Trần's book is quoted as saying that Laos reverted to UT+7 on 1955-04-15.
+# Trần's book says that Laos reverted to UT+7 on 1955-04-15.
 # Also, guess that Laos reverted to UT+7 on 1945-09-02, when Vietnam did;
 # this is probably wrong but it's better than guessing no transition.
 Zone	Asia/Vientiane	6:50:24 -	LMT	1906 Jul  1