HIV-1 subtypes distributed among the heterosexsual population in Bulgaria - Ivailo Alexiev; Reneta Dimitrova; Lora Nikolova; Asya Kostadinova; Anna Gancheva; Ivaylo Elenkov; Nina Yancheva; Mariyana Stoycheva; Ttetsa Doychinova; Liliya Pekova; Maria Nikolova (Elsevier, 2018)