Paidion,
Yes, those texts are what I had in mind (though Paul didn't, himself, actually call it "the Lord's day"). "The Lord's day" in Revelation is considered by all reputable scholars to be indicative of a Sunday.
As to (non-canonical) Early Christian Writings; the Didache, which might date as early as 70AD, makes specific reference to "the Lord's day" as
the holy day Christians are to set aside for worship. Ignatius does the same (and he predates Justin).
more general comments
Orthodox Jews do not post on the internet on Sabbaths, as they consider it a type of work and as not-keeping the Sabbath day holy (go to the Beliefnet Orthodox Judaism forums and one will see they "close shop" every Friday evening at sundown)....
In the early (Post-NT) Christian literature, some Christians observed as "holy days for the Lord"
both the (Jewish) Sabbath day,
and the Lord's day. In other words, they set aside two days a week.
Others, from the earliest times, seemed to have observed one or the other (just one).
Early on; debates about: Which day is the right one? happened. Church officials had allowed for "one or both" till at least the Council of Laodicea of 364AD.
Jewish-Christians, however, continued to exist as "groups" into the 6th century. It was right around then, if I'm not mistaken, that they basically disappeared from church history.
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a short thread-related quiz for anyone
I live in west-central Ohio; very close to Dayton, OH
(having the same local time, and sunrise/sunset times).
On Feb 1, 2008, I:
--was studying the Bible and praying from 5PM till I got ready and....
--drove to a Bible study at 6PM
--which began at 6:30PM (7 people in attendance)
--drove home afterwards, arriving at 7:45PM
--made some theology-related posts on the internet
--had my "evening" (bedtime) prayer and went to sleep
On Feb 2, 2008, I:
--woke up at 7:45AM and prayed
--studied the Bible, rested, and prayed (during daylight hours)
--did not go anywhere (to work, shop, or buy anything)
--ate pre-prepared meals
--did not post on the internet
--drove to a church service at 6:45PM
--which started at 7PM and ended at 8:30PM
--drove straight home, arriving at 8:45PM
--walked a total of only (maybe) 250 feet, tops
--continued to study the Bible and pray till 12:00AM, Feb 3, 2008
--from the time I got up till Feb 3rd; the entire time was set aside as "holy to the Lord"
Did I set aside (and/or observe) the sabbath day?
Did I set aside (and/or observe) the Lord's day?
Did I do anything wrong or make any technical, or other, mistakes?
I'm offering this link for assistance in answering the questions:
http://aa.usno.navy.mil/data/docs/RS_OneYear.php
Good luck on the quiz!

Rick