1. i>Sulla condizione necessaria e sufficiente affinch un triangolo sia acutangolo, rettangolo oottusangolo
2. i>Problem E2388
3. D. S. Mitrinovic, J. E. Pečarić, V. Volence, Recent Advances in Geometric Inequalities, Contributions to Nonlinear Functional Analysis, Dordrecht, The Netherlands,
4. i>Proving inequalities in acute triangle with difference substitution
5. i>An inequality for non-obtuse triangles