def citedby_pid(self, pid, metaonly=False, from_heap=True):
if from_heap is True:<EOL><INDENT>result = citations.raw_data(pid)<EOL>if result and '<STR_LIT>' in result and metaonly is True:<EOL><INDENT>del(result['<STR_LIT>'])<EOL>return result<EOL><DEDENT>if result:<EOL><INDENT>return result<EOL><DEDENT><DEDENT>result = self.client.citedby_pid(pid, metaonly=metaonly)<EOL>try:<EOL><INDENT>return json.loads(result)<EOL><DEDENT>except:<EOL><INDENT>return None<EOL><DEDENT>
Retrieve citedby documents from a given PID number.

pid: SciELO PID number
metaonly: will retrieve only the metadata of the requested article citations including the number of citations it has received.
from_heap: will retrieve the number of citations from a preproduced report, it will not fetch the api. Much faster results but not extremelly updated.