Send the following on WhatsApp
Continue to ChatFamily of surface with a common null geodesic - https://avesis.omu.edu.tr/yayin/90731a21-6130-4ffa-af28-b6098f0f8c7d/family-of-surface-with-a-common-null-geodesic
Family of surface with a common null geodesic - https://avesis.omu.edu.tr/yayin/90731a21-6130-4ffa-af28-b6098f0f8c7d/family-of-surface-with-a-common-null-geodesic