TY  - GEN
AU  - Somia Saad Mohamed Saad
AU  - lmam I. Ahmed , 
AU  - Mohamed A. Sharaf , 
AU  - Mohamed S. Aboulazm , 
TI  - Changes in Frequences of Double - Mode RR - Lyrae Stars in M15  / 
PY  - 1997///
CY  - Cairo : 
PB  - Somia Saad Mohamed Saad , 
N1  - Thesis(ph.D.) - Cairo University - Faculty of Science - Department of Astronomy and Meteorology
UR  - http://172.23.153.220/th.pdf
ER  -