question about Argentina 1946 - 1963

In the Argentina timezone rules I find a strange fact: continuous DST from Oct 1946 to Oct 1963. The rules are: Rule Arg 1946 only - Mar 1 0:00 0 - Rule Arg 1946 only - Oct 1 0:00 1:00 S Rule Arg 1963 only - Oct 1 0:00 0 - Rule Arg 1963 only - Dec 15 0:00 1:00 S There are no other rules affecting the years 1946 or 1963 or any year in between. This means that Argentina was continuously on DST. Is this really correct, and what are the sources for that?