id	keyword
cpos-524	birth
cpos-524	second
cpos-524	rst
cpos-524	age
cpos-524	women
cpos-524	fertility
cpos-524	spain
cpos-524	france
cpos-524	rst birth
cpos-524	fi rst
cpos-524	intervals
cpos-524	family
cpos-524	birth intervals
cpos-524	time
cpos-524	child
cpos-524	et al
cpos-524	mothers
cpos-524	cohort
cpos-524	education
cpos-524	research