code: def getCitations(self, field = None, values = None, pandasFriendly = True):
          retCites = []
          if values is not None:
              if isinstance(values, (str, int, float)) or not isinstance(values, collections.abc.Container):
                  values = [values]
          if field is not None:
              for cite in self.get('citations', []):
                  try:
                      targetVal = getattr(cite, field)
                      if values is None or targetVal in values:
                          retCites.append(cite)
                  except AttributeError:
                      pass
          else:
              retCites = self.get('citations', [])
          if pandasFriendly:
              return _pandasPrep(retCites, False)
          return retCites