Please note that you wrote to the ResearchGate community, not to the RG team. However, it not worth writing to them, they will not add citations manually. All citations shown in ResearchGate were found by an automated algorithm. See also these discussions on missing citations:

https://www.researchgate.net/post/Why_are_some_citations_not_visible_on_ResearchGate_and_Google_Scholar

https://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 Professor Wolfgang R. Dick,

Thank you very much for the information.

Indeed, I mistakenly posted the question on the wrong page.

Kind regards - M. HSINO

Dear Mahmoud Hsino In addition to what is already indicated by Wolfgang R. Dick I can add that in this case the reason is that:

The paper you found is (as far as I can see) not present in RG. Only when the author upload the paper here on RG (since the journal has no link to the existing database of journals here on RG) there might be a chance that the algorithm/search engine of RG might pick the two citations up.

Best regards.

Dear Professor Rob Keller,

Thank you very much for the information – indeed, you are right.

Kind regards,

Mahmoud