Footnote:
Repr. from Proceedings of the 7th International Conference on Soil Mechanics and Foundation Engineering, Mexico 1969, and from Proceedings of Specialty Sessions Nos. 2 and 8. - Enth.u.a.: Negative skin friction for long piles driven in clay / Bengt Fellenius & Bengt Broms. Negative skin friction on piles in clay - a literature survey / Bengt Fellenius