def count_referneces_from_the_year(step, year):
	world.references_count = 0
	references = pm.refs(world.filecontent)
	for ref in references:
		try:
			if int(ref['year']) == int(year):
				world.references_count += 1
		except(KeyError):
			continue
def count_the_number_of_references_from_the_journal(step, journal):
	if (journal == 'None'):
	  journal = None
	world.references_count = 0
	references = pm.refs(world.filecontent)
	for ref in references:
		try:
			if ref['source'] == journal:
				world.references_count += 1
		except(KeyError):
			if journal == None:
				world.references_count += 1