Sources for roots- skirret and yacon?

Long time lurker, first time posting. I'm putting my garden back into shape after a long time of neglect and I'm looking for sources for perennial root vegetables, especially yacon and skirret.  They are nowhere to be found,  out of stock or those seed companies are long gone. Any suggestions are appreciated! Thank you!

i’ll have yacon available once i harvest, but not now in the middle of the growing season. i agree, most commercial sources seem to be out of stock.