Experiences of stigma and support reported by participants in a network intervention to reduce HIV transmission in Athens, Greece; Odessa, Ukraine; and Chicago, Illinois by Williams, LD, Korobchuk, A, Pavlitina, E, Nikolopoulos, GK, Skaathun, B, Schneider, J, Kostaki, E-G, Smyrnov, P, Vasylyeva, TI, Psichogiou, M, Paraskevis, D, Morgan, E, Hadjikou, A, Downing, MJ, Hatzakis, A, Friedman, SR