1. R. C. Tolman, Relativity, Thermodynamics, and Cosmology, Oxford 1934, p. 252, formula (98.6).
2. R. C. Tolman, p. 243, formula (95.8); cfr. too: G. Järnefelt, Das Einkörperproblem in dem sich ausdehnenden Raume der Einstein– De Sitter'schen Welt, Ann. Acad. Sc. Fenn., Ser. A, I., 12, 1942, p. 21.
3. Cfr. G. Järnefelt, loc. cit., p. 21, formulae (40).
4. G. C. McVittie, The Mass-Particle in an Expanding Universe, M. N. 93, 5, 1933, pp. 325–339.
5. G. C. McVittie, loc. cit., p. 329, formulae (10) and (11).