@online{ timsrc, author = "Grammig, Joachim", title = "Lecture Quantitative Methods in Economics and Business Administration, 5. Lesson", publisher = "Universität Tübingen", year = "2025", month = "Oct", day = "27", url = "https://timms.uni-tuebingen.de:443/tp/UT_20251027_001_ws2526quantmethwiwi_0001", urldate = "2025-11-12" }