Alcohol use, cigarette smoking, vaping and number of sexual partners: A cross‐sectional study of sexually active, ethnically diverse, inner city adolescents oleh Rosalie Bartholomew Dr, Sarah Kerry‐Barnard, Nicholas Beckley‐Hoelscher Dr, Rachel Phillips, Fiona Reid, Charlotte Fleming, Agata Lesniewska, Freya Yoward Dr, Pippa Oakeshott