what are the four most commonly given procedures for patients who have an age 30s?
select d_icd_procedures.short_title from d_icd_procedures where d_icd_procedures.icd9_code in ( select t1.icd9_code from ( select procedures_icd.icd9_code, dense_rank() over ( order by count(*) desc ) as c1 from procedures_icd where procedures_icd.hadm_id in ( select admissions.hadm_id from admissions where admissions.age between 30 and 39 ) group by procedures_icd.icd9_code ) as t1 where t1.c1 <= 4 )