Either on Internet Archive or from second-hand bookshops, I'm trying to get hold of the books of stories in the collection Sgéaluidheacht Chúige Mumhan. The one I can't seem to find is number four. Does anyone know what the title is and if it's available from anywhere?
Here are the titles that I've found so far:

1 Sgeuluidheacht Chúige Mumhan - Céad Cuid - Ó Laoghaire Peadar (apparently this is the first volume)

2 Páidín Ó Dálaigh - An Dara Roinn

3 Rí na mBréag - An Treas Roinn

4 ?

5 An Fiolar Faelltach - An Cúigeadh Roinn

6 Máire Ní Rógáin - An Seiseadh Roinn

7 Oileán na gCúig mBeann .i. An tSeachtmhadh Roinn de Sgéaluidheacht Chúige Mumhan ag Pádraig Ó Laoghaire (were they brothers ?)

These books are also called Leabhairíní Gaedhilge le haghaidh an tSluaigh.

ça y est, j'ai trouvé -

The first one in this series is - Na Trí Préacháin (An Chéad Roinn..) and the fourth is An Chroch Gheal - .i. an ceathramha roinn - all by Pádraig Ó Laoghaire. But neither of these two are available on-line or elsewhere.

Leabhair? Scéalta is ea iad.

Seo chugat i leabhar amháin:
https://archive.org/details/sgeuluidheachtch00lauoft
nó
https://archive.org/details/sgeuluidheachtc00unkngoog

i leabhraíní:
Oileán na gCúig mBean:
https://archive.org/details/oilennagcigmbea00laoggoog
An fiolar fealltach:
https://archive.org/details/anfiolarfeallta00laoggoog
Máire Ní Rógáin:
https://archive.org/details/mirenrginseisear00laog
Rí na mBreag
https://archive.org/details/rnambragtreasroi00laog

Ceart go leor - go raibh maith agat.