def read_links(links_filename):
	"""Read links file and store in reference list"""
	links_list = []
	with open(links_filename) as in_f:
		is_header = True
		for line in in_f:
			if is_header:
				is_header = False
				continue
			row = line.strip().split(',')
			links_list.append(int(row[0]))
	return links_list