Citations in knitting? What's polite?

[aedifica]

If I'm writing an academic paper and I find some information I need in someone else's paper, of course I cite them. If I'm writing a knitting pattern and I find something I want to use in someone else's pattern, do I cite them? Or do I just write up the pattern and it's fine as long as I'm not copying someone else's whole pattern?

Bringing an academic background to knitting leads to unexpected questions. :-)