Langevich, H. Letter, To: Sister Olya From: Mother Helena Langevich, [n.d.].
शिकागो शैली (17वां संस्करण) प्रशस्ति पत्रLangevich, Helena. Letter, To: Sister Olya From: Mother Helena Langevich, [n.d.].
एमएलए (8वां संस्करण) प्रशस्ति पत्रLangevich, Helena. Letter, To: Sister Olya From: Mother Helena Langevich, [n.d.].
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