Langevich, H. Letter, To: Sister Olya From: Mother Helena Langevich, May 9, 1912.
शिकागो शैली (17वां संस्करण) प्रशस्ति पत्रLangevich, Helena. Letter, To: Sister Olya From: Mother Helena Langevich, May 9, 1912.
एमएलए (8वां संस्करण) प्रशस्ति पत्रLangevich, Helena. Letter, To: Sister Olya From: Mother Helena Langevich, May 9, 1912.
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