A systems analysis and improvement approach to optimizing syringe services programs' delivery of HIV testing and referrals: Study protocol for a parallel-group randomized controlled trial (SAIA-SSP-HIV). - Bazzi AR; Roth AM; Akiba CF; Huffaker SL; Patel SV; Smith J; Laurano R; Orme S; Zarkin GA; Morgan-Lopez A; Lambdin BH (PloS one, 2025)