1. BS 806: Design and construction of ferrous piping installations for and in connection with land boilers,1986
2. Uber Die formandiger Rohre, Inbesondere Federnder Ausgleichsrohre;von Karman;Z. Verduet. Ing.,1911
3. Experiments on short-radius pipe bends;Gross,1953
4. Properties of thin-walled curved tubes of short radius;Pardue;Trans. ASME,1951