A multi-level explanatory-sequential mixed-methods study of perinatal toxicology practices in New York State: Protocol - Sugy Choi; Elizabeth Knopf; Erin Kim; Charles J. Neighbors; Carolyn A. Berry; Erinn Hade; Chau Trinh-Shevrin; Mishka Terplan; Neil S. Seligman; David J. Garry; Jennifer McNeely (PLoS ONE, 2025)