this finds citations in text-files based on the pattern "four digits inside parentheses". outputs textfile with list

citation_finder.py

import os
import re

os.chdir("E:\\PhD\\Chapters\\2_Sondes_2015")

file = open(os.path.join(os.getcwd(),"sondes_manuscript.txt"), encoding="utf8")

findings = []

for line in file:
    par_content = re.findall(r'\((.*?)\)',line)
    for item in par_content:
        res = re.search(r"\d{4}", item)
        if res:
            citations = item.split("; ")
            for citation in citations:
                findings.append(citation)


res_file = open(os.path.join(os.getcwd(),"out.txt"), 'w')
for item in findings:
    res_file.write(item + "\n")
res_file.close()