تبولوجيا الدونات

1. Topology [Internet]. Maths Careers. 2014 [cited 5 January 2022]. Available from: هنا

2. Le Roux M, Hood M. When is a coffee mug a donut? Topology explains it [Internet]. Phys.org. 2016 [cited 5 January 2022]. Available from: هنا

3. O Connell C. Topology explained – and why you're a donut [Internet]. Cosmos Magazine. 2016 [cited 5 January 2022]. Available from: هنا