Chemical Safety and Hazard Investigation Board. [Valero refinery asphyxiation incident].
Chicago-viite (17. p.)Chemical Safety and Hazard Investigation Board. [Valero Refinery Asphyxiation Incident].
MLA-viite (9. p.)Chemical Safety and Hazard Investigation Board. [Valero Refinery Asphyxiation Incident].
Varoitus: Nämä viitteet eivät aina ole täysin luotettavia.