S. Pancharatnam (1956). "Generalized Theory of Interference, and Its Applications. Part I. Coherent Pencils". Proc. Indian Acad. Sci. A. 44 (5): 247–262. doi:10.1007/BF03046050. S2CID118184376.
G. Herzberg; H. C. Longuet-Higgins (1963). "Intersection of potential energy surfaces in polyatomic molecules". Discuss. Faraday Soc. 35: 77–82. doi:10.1039/DF9633500077.
Hart, John B.; Miller, Raymond E.; Mills, Robert L. (1987). "A simple geometric model for visualizing the motion of a Foucault pendulum". American Journal of Physics. 55 (1): 67–70. Bibcode:1987AmJPh..55...67H. doi:10.1119/1.14972.
Somerville, W. B. (1972). "The Description of Foucault's Pendulum". Quarterly Journal of the Royal Astronomical Society. 13: 40. Bibcode:1972QJRAS..13...40S.
Hart, John B.; Miller, Raymond E.; Mills, Robert L. (1987). "A simple geometric model for visualizing the motion of a Foucault pendulum". American Journal of Physics. 55 (1): 67–70. Bibcode:1987AmJPh..55...67H. doi:10.1119/1.14972.
S. Pancharatnam (1956). "Generalized Theory of Interference, and Its Applications. Part I. Coherent Pencils". Proc. Indian Acad. Sci. A. 44 (5): 247–262. doi:10.1007/BF03046050. S2CID118184376.