TY  - BOOK
AU  - Mathias, Kirk E. 
AU  - Mathias, Kirk E. 
TI  - Can a smartphone application improve girls' physical activity behavior during weekend/
U1  - DPer613.7105 J74 January-December 2020 v91 no 1-9 
PY  - 2020///
CY  - Virginia ; 
PB  - American Alliance for Health, 
ER  -