Handling of MARC fields in citation styles should be changed as follows:
1. If there are relator codes in $4, only $4 aut and cmp should be considered as author, relator codes $4 edt, ill, ivr, trl and drt should be treated as contributors. Entries with other $4 codes should be ignored for citation.
2. If there are no relator codes $4 in the record, field 100 should be considered as author, field 700 as contributor.
Benefits: Citiation styles get independent from cataloguing language as they are now by using $e. Also citation styles work independent from the fact, if the record is catalogued according to RDA or - as is the case with many records in many catalogues - by older rules like AACR2.