Can (should?) I cite a personal communication from another paper? In my specific case, I want to express that a certain metric is not available yet, but it is the focus of ongoing research. I know this from the following section of Warton et al. 2012:
but it is the subject of ongoing research (M. J.Anderson, pers. comm.).
Do I just cite the Warton paper or use the approach suggested in Citing a Work that Cites a Personal Communication for tabular data?