BS: A,7 vs dealer A in single deck

I am wondering if anyone knows why the correct move according
to basic strategy for A,7 is sometimes to Hit vs dealer Ace
and sometimes to Stand? When does one do one over the
other?(Ken's posting of BS shows to Hit while books like
MDBJ say to stand for single deck Las Vegas rules.

Thanks,
queued

Here's a recent answer to this question:

[thread=155](A,7) vs A[/thread]

thanks for the info

that explains it ------- thanks