俱舍論記 8.165

8.165

「若復不誦至何名中般」者，第四五不還經。既言中般，明有中有。

Regarding "If, furthermore, one does not recite [...] what would be meant by 'attaining parinirvāṇa in the intermediate state'?": this is the fourth, the discourse on the five non-returners. Since it speaks of "attaining parinirvāṇa in the intermediate state" (antarā-parinirvāyin), it is clear that there is an intermediate existence.