Indexing Google Scholar International Impact Factor Services Directory of Research Journal Indexing Websquash EZB-University Library of Regensburg Open Academic Journals Index Directory of Indexing and Impact Factor (DIIF) Citefactor Pubicon Science Index Scientific Indexing Services Bibliothekssystem Universität Hamburg Refseek InfoBase Index SJIF – Scientific Journal Impact Factor Universal Impact Factor Social science Research Center Berlin hochschule hannover – university of applied sciences and arts Jour info Global Impact Factor (GIF) (Impact factor: 0.204) Advanced Science Index Research Bible Technical University of Berlin Universität Leipzig Universität des Saarlandes ILSE – IPN Library Search Engine (1128) Freie Universität Science Impact Factor (Impact Factor: 0.69) Journal Impact Factor (JIF) TU Clausthal WorldCat wissenschaftskolleg zu berlin KVK – Karlsruher Virtueller Katalog Thunderstone Website Catalog (1371) Sjournals TIB (German National Library of Science and Technology) International Institute of Organized Research