(1) Tola E. H. M. (2002). Performance of various no-till furrow openers under different soil and
crop residue conditions. Muellerbader GmbH, Filderstadt, Germany. ISBN 3-86186-397-9.
(2) Michael Ashworth, Jack Desbiolles, and ElKamil Tola (2010). Disc seeding in zero-till farming
systems – A review of technology and paddock issues. Western Australian No-Tillage Farmers’
Association (WANTFA). Northam, Western Australia. ISBN 978-0-646-52876-2