1. Comité Europeen du Béton, Bulletin D Information No. 112, Joint Committee on Structural Safety, 1976.
2. DIN 4026: Rammpfähle, Aug. 1975;
3. DIN 1054: Zulässige Belastungen des Baugrunds, Nov. 1976.
4. and , ‘Varibility among piles of the same foundation’, Proc. 9th International Conference on Soil Mechanics and Foundation Eng. Tokyo (1977).
5. and , ‘Pile bearing capacity prediction versus performance’, ASCE Speciality Conference on Performance of Earth and Earth Supported Structure (1972).