I find that literature cited in most of my papers can not be fully collected by ResearchGate. For example, I cited 37 literatures in a recent paper which I uploaded to ReseachGate in form of PDF as a full text of the record. However, only 35 literatures were recognized by ReseachGate, and among which 11 had no links. See the Figure.
It can be seen from the Fig. that the first literature was collected by ResearchGate, with link and information about comment and citations. The second and third literature were not correctly collected by RG. Both literature have no such information and link. I searched both literature and found that they are deposited in the RG systems.
Is this normal? What should I do to facilitate collection of these literature by RG?