x1 = sitna1 = utka1
cites/quotes/refers to/makes reference to a source, which itself/who themself cites/quotes/refers to/makes reference to a source, which itself/who themself in turn cites/quotes/refers to/makes reference to source, ..., which itself/who themself cites/quotes/refers to/makes reference to source x2 = sitna2 = utka2, via intermediate path-connecting steps x3 = utka3 (ordered list; ce'o), all for the same information/statement x4 = sitna3 (du'u).
marks a construct as being a reference/allusion - explicit marker of divorce/isolation of a construct from any external allusions that may come to mind