1. AASHTO LRFD Bridge Design Specifications. 8th ed. Washington, DC; 2017.
2. Stresses in external tendons at ultimate;Roberts-Wollmann;ACI Struct J,2005
3. Strength and ductility of a three-span externally post-tensioned segmental box girder bridge model. Research report no;MacGregor,1989
4. BSI (British Standards Instituition). Structural use of concrete. BS8110, London; 2001.
5. DIN (Deutches Institut fur Normung). (1980). Spannbeton, dautile mit vorspannung ohne verbund. DIN 4227, Teil 6, Berlin.