1. Abdullah S. 2020. 3 Types of Earth Movements: Earth Rotation, Earth Revolution and Precession. https://notesread.com/3-types-earth-movements-earth-rotation-earth-revolution-precession/
2. AG (Australia Government) 2017. http://www.agriculture.gov.au/ag-farm-food/crops/wheat.
3. AG (Australia Government) 2016. Australia’s Reference climate Station Network. http://www.bom.gov.au/climate/change/reference.shtml.
4. ASKINGLOT 2019. What is the precision cycle? https://askinglot.com/what-is-the-precession-cycle
5. AWXB, “Australian wheat,” 2018, http://www.awb.com.au/customers/australianwheat/.