Elkies, Noam D. (1996), "On numbers and endgames: combinatorial game theory in chess endgames", Games of no chance (Berkeley, CA, 1994), Math. Sci. Res. Inst. Publ., vol.29, Cambridge: Cambridge Univ. Press, pp.135–150, MR1427963.
That is, not every position in a partisan game can have a nimber as its value, or else the game would be impartial. However, some nimbers can still occur as the values of game positions; see e.g. dos Santos, Carlos Pereira (2011), "Embedding processes in combinatorial game theory", Discrete Applied Mathematics, 159 (8): 675–682, doi:10.1016/j.dam.2010.11.019, MR2782625.
That is, not every position in a partisan game can have a nimber as its value, or else the game would be impartial. However, some nimbers can still occur as the values of game positions; see e.g. dos Santos, Carlos Pereira (2011), "Embedding processes in combinatorial game theory", Discrete Applied Mathematics, 159 (8): 675–682, doi:10.1016/j.dam.2010.11.019, MR2782625.
