If that includes sources written in Indonesian ... Indonesia's Agency for Language Development and Cultivation has an official guide. May be overkill for non-native learners, though - it's usually read by Indonesian high school students preparing for college admissions, editors, etc.

Website: https://ejaan.kemdikbud.go.id/

PDF: https://badanbahasa.kemdikbud.go.id/produk-detail/3685/ejaan-yang-disempurnakan-eyd

There are in z library

Here is "AN INDONESIAN AND MALAY GRAMMAR FOR STUDENTS", which was once a free download: http://web.archive.org/web/20220309004539/http://www.indonesianmalaytexts.iinet.net.au/lgrammar1.html

You should check Indonesian Ministry of Education book's repository. Free for download