TY  - JOUR 
T1  - Half-factoriality in subrings of trigonometric polynomial rings
JO  - TEMA (São Carlos)
A1  - Ullah, Ehsan
A1  - Shah, Tariq
SN  - 2179-8451
UL  - 10.1590/S2179-84512013005000003
VL  - 14 
Y1  - 2013
PB  - Brasil 
ER  -