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Guilfoyle, B.; Klingenberg, W. (2020). «Fredholm-regularity of holomorphic discs in plane bundles over compact surfaces». Ann. Fac. Sci. Toulouse Math. Série 6 29 (3): 565-576. S2CID119659239. arXiv:1812.00707. doi:10.5802/afst.1639.
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Titus, C. J. (1973). «A proof of a conjecture of Loewner and of the conjecture of Carathéodory on umbilic points». Acta Math.131 (1–2): 43-77. S2CID119377800. doi:10.1007/BF02392036.
Guilfoyle, B.; Klingenberg, W. (2004). «Generalised surfaces in ». Math. Proc. R. Ir. Acad. 104A (2): 199-209. S2CID118128548. doi:10.1353/mpr.2004.0013.
Guilfoyle, B.; Klingenberg, W. (2020). «Fredholm-regularity of holomorphic discs in plane bundles over compact surfaces». Ann. Fac. Sci. Toulouse Math. Série 6 29 (3): 565-576. S2CID119659239. arXiv:1812.00707. doi:10.5802/afst.1639.