Sweet kittens need a home (Tucson)

I found these 2 kittens outside my townhouse on Saturday.
The vet scanned them for microchips, which they don't have.
They are white with light brown ears, probably siblings 4 or 5 months old, and are a bonded pair.
One is a little bigger and is so sweet with the smaller one.
No one in the neighborhood knows anything about them.
They're not feral.
They were scared and shy at first, but after they got used to me they'll climb onto my lap or chew my shoe laces.
They are the sweetest little kittens, and I would love to find a good home for them where they could be together.