^Weber، Max (1961). General Economic History. New York: Collier Books. صفحة 23. [...] the German plow [...] made [...] criss-cross plowing unnecessary, and for its use the division into long strips was most appropriate. The size of the separate strips was usually determined in this connection, by the amount which an ox could plow in a day without giving out - hence the Gernan names Morgen (English, 'morning' but equivalent to an acre) or Tagwerk (English, day's work).