My father-in-law's paternal grandmother was Sally Handler. (Also known as Roza, Rozalia, and Szali, as I shared at Different Names-Same Person.) I shared some information about her at Mystery Monday - Finding a Jewish Great-Grandmother, where I noted that JewishGen's Online Burial Registry (JOWBR) has an entry for Sally Handler:
She is Chaya Sara bat [daughter of] Zvi.
In Great-Grandmother Handler Married Twice, I shared a 1911 marriage record for Rosalie Hendler [sic] and Samuel Goodman where her parents are listed as Harry Hendler [sic] and Anna Stern.
I therefore theorize that this Handler line is:
Harry Handler = Anna Stern
And the awkward thing about this line is that Sally Handler married her father's brother, Aaron Handler who was about 20 years her senior and a widower with children.