Langevich, H. Letter, To: Sister Olya From: Mother Helena Langevich, [n.d.].
Chicago-referens (17:e uppl.)Langevich, Helena. Letter, To: Sister Olya From: Mother Helena Langevich, [n.d.].
MLA-referens (8:e uppl.)Langevich, Helena. Letter, To: Sister Olya From: Mother Helena Langevich, [n.d.].
Varning: dessa hänvisningar är inte alltid fullständigt riktiga.