The first stanza of Robert Frost's "Stopping by Woods on a Snowy Evening" reads as follows in its original publication in New Hampshire (1923):

Whose woods these are I think I know.
His house is in the village though;
He will not see me stopping here
To watch his woods fill up with snow.

I had always thought the first line was:

Whose woods these are I do not know.

(Incidentally, this would resolve this difficulty.)

Now of course it is possible that I had simply misremembered the words, but an internet search of the phrase "whose woods these are I think I know" turns up a lot of results in which people seem to think that this is indeed the line in Frost's poem.

Is there any evidence of different versions by the author? Alternatively, is there any evidence of someone (deliberately, or unintentionally) altering the text, such that others might have subsequently used a faulty source and learned the poem incorrectly from the start?

The first stanza of Robert Frost's "Stopping by Woods on a Snowy Evening" reads as follows in its original publication in New Hampshire (1923):

Whose woods these are I think I know.
His house is in the village though;
He will not see me stopping here
To watch his woods fill up with snow.

I had always thought the first line was:

Whose woods these are I do not know.

(Incidentally, this would resolve this difficulty.)

Now of course it is possible that I had simply misremembered the words, but an internet search of the phrase "whose woods these are I do not know" turns up a lot of results in which people seem to think that this is indeed the line in Frost's poem.

Is there any evidence of different versions by the author? Alternatively, is there any evidence of someone (deliberately, or unintentionally) altering the text, such that others might have subsequently used a faulty source and learned the poem incorrectly from the start?