Nisan 5718.
... DPH"CH [1] regarding what is written about Purim – like Purim. See also Tzena U'Rena 561 (57b). Torah Or by our master the Alter Rebbe in the additions to Magen Avraham (121a). [2]
Summary
This letter points to sources that discuss the deep connection between Purim and Yom Kippur, encouraging further study of their shared themes in chassidic literature.