I have two conference papers published about one year ago in the same conference proceeding. One is finally get indexed by Scholar (it seems after being cited - not self-citing). Another is still not indexed. I skimmed all of Google's documentation related to indexing and tried various solutions. The papers are available from multiple places (the conference proceeding, the university's web site, my CV web site). No results. I have no idea about Google's criteria for indexing. Sometimes, it indexes even some presentation and drafts from my web site. Are there any tricks to arrange this and push Google a bit to index desired publications which it ignores so far?

The papers are:

(1, indexed): https://doi.org/10.5281/zenodo.1346671

(2, unindexed, added manually to the profile, unsearchable through Scholar): https://doi.org/10.5281/zenodo.1314215

====UPDATE (copy-paste from an answer)===

Everything has been successfully indexed (no extra actions from my side). It's seemingly a matter of time (about two years, in my case).

===MORE===

It looks that GS uses a trustworthiness parameter for paper sources - personal small websites have much lower trust in comparison to publishers. Thus, it can take a long time to get something indexed from a personal site. On the other side, papers from large publishers get indexed almost immediately. It makes sense. The only problem I have with this is that green-open-access version papers published on my site can be hardly properly merged with the publisher's version in google scholar - i.e., a merged version (marked with *) are appeared merged only on my GS profile, but not in the results of GS search. E.g., my paper doi.org/10.4018/978-1-5225-7927-4.ch002 has been marked to be merged for more than two years, but till now it appears as two different papers in the result of GS search (and as a single paper in my profile marked by *). The result is the very low visibility of the paper.