Reference for Bava Metzia 2:3
מָצָא אַחַר הַגַּפָּה אוֹ אַחַר הַגָּדֵר גּוֹזָלוֹת מְקֻשָּׁרִין, אוֹ בִשְׁבִילִין שֶׁבַּשָּׂדוֹת, הֲרֵי זֶה לֹא יִגַּע בָּהֶן. מָצָא כְלִי בָּאַשְׁפָּה, אִם מְכֻסֶּה, לֹא יִגַּע בּוֹ, אִם מְגֻלֶּה, נוֹטֵל וּמַכְרִיז. מָצָא בְגַל אוֹ בְכֹתֶל יָשָׁן, הֲרֵי אֵלּוּ שֶׁלּוֹ. מָצָא בְכֹתֶל חָדָשׁ, מֵחֶצְיוֹ וְלַחוּץ, שֶׁלּוֹ, מֵחֶצְיוֹ וְלִפְנִים, שֶׁל בַּעַל הַבָּיִת. אִם הָיָה מַשְׂכִּירוֹ לַאֲחֵרִים, אֲפִלּוּ בְתוֹךְ הַבַּיִת, הֲרֵי אֵלּוּ שֶׁלּוֹ:
If he found behind a gappah [a wall-filling of wood or reeds] or behind a fence [of stones], tied fledglings, [tied by their wings. Since all men tie them thus, this is not a siman.], or in paths in the fields, he should not touch them. [For we assume that they were secreted there, and if they are taken, the owners will not have a siman. Therefore, they should be left there until the owners come and take them.] If he found a vessel in the rubbish heap, if it is covered, he should not touch it, [this not being a lost object about which he is exhorted (Deuteronomy 22:3): "You shall not be able to ignore it," for it is guarded.] If it is not covered, he takes it and calls it out. If he found it in a heap or in an old wall, it is his. [For he can tell the owner of the heap or of the wall that it belonged to the Emorites driven out by our ancestors. This, if it be extremely mouldy, indication of its having lain there for a very long time.] If he found it in a new wall — in the outer half, it is his; in the inner half, it is the (home) owner's. [In one of the holes of a wall close to the public domain, if he found it from half the thickness of the wall facing out, it is his. For we say that one of the men in the public domain placed it there and forgot it. And the mould upon it indicates its having been there a long time, so that the owner must certainly have despaired of it. This, only in the instance of a tongue of gold, a piece of silver, and the like. But if it were a vessel, and in it money — if the mouth of the vessel faces outwards, it is his; if inwards, it is the (home) owner's. If he rented it to others, even (if he found it) inside the house, it is his, [ it not being known whose it is, and the owner's having despaired.]