This means that ResearchGate's automated algorithm has not yet identified these citations, e.g. because the citing publications are missing at RG, or for other reasons. It is not possible to add citations manually. See also these discussions:

ttps://www.researchgate.net/post/RG-citations-how-are-they-calculated/1

https://www.researchgate.net/post/missing_citation_number/1

https://www.researchgate.net/post/Why_are_some_of_my_citations_not_shown2/1

https://www.researchgate.net/post/Why_the_citation_is_not_shown/1

https://www.researchgate.net/post/How_can_we_add_citation_on_research_gate/1

https://www.researchgate.net/post/How_add_references/1

https://www.researchgate.net/post/Citations_from_RG/1

https://www.researchgate.net/post/citations_in_RG/1

https://www.researchgate.net/post/How_do_you_fix_missing_citations/1

https://www.researchgate.net/post/How_to_add_missing_citation/1

https://www.researchgate.net/post/What_if_I_have_citations_in_the_research_gate_indexed_papers_that_research_gate_does_not_show_them/1

https://www.researchgate.net/post/Question_about_article_submitted_and_references_does_not_appear/1

https://www.researchgate.net/post/RG_system_to_detected_Citations/1

Dear Vagif Sultanly

I noticed that the largest part of the pdf file of the book cannot be searched. If you click on the ‘magnifying glass symbol’ then you will see that nothing of the reference part can be searched (not sure why, perhaps that part of the book is scanned and miss essential info).

Because of this the RG engine is not able to ‘read’ parts (including the references) of the book. Because of this the references at the RG page here is blank.

Best regards.