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muder hassen; ahmed shem; yasmin waleed. "lactational amenorrhoea method in birth spacing". , 1, 1, 2005, 31-36.

hassen, M., shem, A., waleed, Y. (2005). 'lactational amenorrhoea method in birth spacing', , 1(1), pp. 31-36.

hassen, M., shem, A., waleed, Y. lactational amenorrhoea method in birth spacing. , 2005; 1(1): 31-36.