Hello guys, I am working on repeated cross sectional data sets on women (health related) for 36 countries with years ranging from 1990 to 2018. The data are rounds of surveys with intervals ranging from 3 to 9. The number of rounds for each country ranges from 1 to 6. I am expected to create a mother-cohort-fixed effects with birth year and country of residence. Other suggestion is that I incorporate country and year fixed effects. My difficulty is how to do this in stata.