Resumen: Generalized restricted three body problems consist of adding some extra hypotheses to the Restricted three body problem (RTBP) in order to have a new problem, not very different of the original RTBP. However, not any additional hypothesis is allowed; it must satisfy the laws of Physics. Among the several generalizations found in literature, we prove that at least there are two hypotheses that cannot be used, namely: 1) Perturbation in Coriolis and/or centrifugal forces, and 2) primaries are spheroids moving on elliptical orbits. Idioma: Inglés DOI: 10.1007/s10509-024-04286-7 Año: 2024 Publicado en: ASTROPHYSICS AND SPACE SCIENCE 369, 22 (2024), 2-7 ISSN: 0004-640X Factor impacto JCR: 1.5 (2024) Categ. JCR: ASTRONOMY & ASTROPHYSICS rank: 52 / 84 = 0.619 (2024) - Q3 - T2 Factor impacto SCIMAGO: 0.378 - Space and Planetary Science (Q3) - Astronomy and Astrophysics (Q3)