Which sūtras about cosmology are being referenced?

When you are taught to write essays in high school, you are taught you must provide references for your assertions made.

The Wikipedia article is largely unreferenced (with only 5 footnotes) therefore gives the impression of lacking in truthful speech, which cannot be Buddhist.

To begin this topic, the Buddhism commentaries refer to various laws of nature, called the Five Niyama. In summary, the five Niyama separate the physical from the mental. Where as the Wikipedia article seems to vaguely assert a causal relationship between the physical (universe) and the mental (kamma), when it convolutedly says: "The entire universe is said to be made up of five basic elements of Earth, Water, Fire, Air and Space. Buddhist cosmology is also intwined with the belief of Karma."

The Wikipedia article seems to venture into unsubstantiated territory when it seems to depart from the notion of personal kamma into the sphere of collective kamma, when it says: "As a result, some ages are filled with prosperity and peace due to common goodness, whereas other eras are filled with suffering, dishonesty and short lifespans."

Obviously, a word from the suttas that is important to the Wikipedia article is the word 'loka'. 'Loka' means 'world' and 'loka' is often described as something arising & ceasing within the mind, such as in the suttas AN 4.45, SN 12.44 & MN 79. Some translators translate 'loka' as 'cosmos', which makes the interpretations even more materialistic & superstitious. Therefore, when suttas use the word 'loka', in relation to 'kamma' & the 'dibbacakkhu' mentioned in the Wikipedia (specifically from sutta MN 4), it is debatable if this 'world/loka' is merely mental or otherwise another place of existence.

For example, there are suttas, such as SN 35.135, which seem to say heaven & hell occur within the mind, in the here & now.

Similarly, a sutta such as SN 56.47, which is a favourite for misinterpretation by materialist eternalists, seems to clearly say the "human state" is a mental state of virtue & wisdom (rather than a biological state of h*m*sapienism & amoral Marxist uniformity).

Again, AN 6.39 is a sutta that equates the realms of godly, human, animal, ghost & hell with mental states.

Iti 93 seems to literally say the realms are comprised of people/men or mortals (macca).

Again, there are suttas such as MN 37 (where Sakka King of the Gods lives in a palace with sexy female nymphs), SN 11.5 (where the benevolent gods & demonic gods are debating how to govern people), AN 3.37 (where the Four Great Kings are concerned with human affairs), AN 4.53 (where a moral husband or wife is called a 'god') & AN 4.190 that says a monk that has attained jhana is a god that give the impression the gods are merely designations for people who have attained a high state of power, meditation or virtue. It is actually difficult to conclude what these various godly realms are referring to in the suttas.

Another important sutta for the eternalist cosmologists is DN 27. The bizzare ideas in DN 27 (about beings are mostly headed for the realm of streaming radiance) are also found in the definition of partial eternalism (a wrong view) in DN1. But, more importantly & unambiguously, DN 27 refers to these already existing "beings" (without any explanation of their origin) that later are subject to sexual lust & craving. However, suttas such as SN 23.2, SN 5.10 and SN 12.2 say "beings" are created by craving; rather than unexplained created beings generate craving, per DN 27.

A great error in the Wikipedia article says: "The vertical cosmology is divided into three realms, or dhātus: the formless realm (Ārūpyadhātu), corresponding to the formless jhanas; the form realm (Rūpadhātu), corresponding to the rūpa jhānas; and the desire realm (Kamadhātu)." The terms here (kamadhātu, rūpadhātu & arūpadhātu) are from MN 115 yet in MN 115 these three dhatu (elements) are merely three from many different other kinds of elements. This idea in the Wikipedia article appears to be a common perversion of the notion of Three Bhava, which is found in SN 12.2 and AN 3.76. "Bhava" in the suttas is a mental state or "asava", as defined in many places, such as MN 9. "Bhava" does not mean a plane of physical existence.

In short, the whole problem of Buddhist Cosmology is it often contradicts the core Supramundane Teachings of the suttas. Therefore, even the most superstitious materialistic establishment conformist translators refer to DN 27 and similar suttas as "mythology", for example, here: The Long Discourses: Dhamma as literature and compilation.

In summary, when briefly browsing the Wikipedia article, it appears to be a mixture of various ideas & interpretations about suttas, sectarian ideas & commentaries. If Wikipedia was a real encyclopedia, it would require its writers to reference their assertions. But, in reality, Wikipedia appears to be similar to StackExchange, where vested interest bloggers just write their personal opinions.

Does anyone know what sūtras the author of the article is referring to?

It's hard to know, isn't it. That article's Talk page begins with two comments:

Citations

• I am going to contemplate whether the majority of this article should be comported to an archive as an annexure accessed from this talk page and start afresh with citations. It is unfortunate that those who iterated this article with such care have been so careless in the provision of their sources.
• I added citations from Foundations of Buddhism [Gethin 1998] for two claims in the introduction. The text, as written, seems very consistent with that text.

The sentence in the article before the one you quoted is,

The Buddhist cosmology as presented in commentaries and works of Abhidharma in both Theravāda and Mahāyāna traditions, is the end-product of an analysis and reconciliation of cosmological comments found in the Buddhist sūtra and vinaya traditions.

I read that as saying that this is an academic topic i.e. requiring textual research or encyclopaedic knowledge -- which you you might find in a book.

I am interested in reading these sūtras, in which the Buddha describes other worlds and states of being, but I am not sure what they are.

I think Piya Tan is good at publishing encyclopaedic cross-references like this, though only from the Pali suttas -- and not so far as I know, from the "works of Abhidharma" nor from "Mahāyāna traditions".

The Search function on his site can be ... well if I just use Google instead e.g. like this:

• https://www.google.com/search?q=site%3Ahttps%3A%2F%2Fwww.themindingcentre.org%2Fdharmafarer+cosmology

Then that finds some of his writings e.g. this one to begin with:

• Early Buddhist cosmology

It's 60 pages, and probably meticulously referenced. Post again if you'd like help with finding any specific sutta that he references.

This page -- https://www.themindingcentre.org/dharmafarer/sutta-discovery/sd-50-59 (which I copy here as a screenshot not as clickable hyperlinked text, click on the link to go to the original) -- has tiny summaries that might help you find the kind of "cosmological" topic that's of interest to you, or least let you see some of the topic in the suttas which some people categorise as "cosmological":