Reference for Bava Metzia 2:9
אֵיזוֹ הִיא אֲבֵדָה, מָצָא חֲמוֹר אוֹ פָרָה רוֹעִין בַּדֶּרֶךְ, אֵין זוֹ אֲבֵדָה. חֲמוֹר וְכֵלָיו הֲפוּכִין, פָּרָה רָצָה בֵּין הַכְּרָמִים, הֲרֵי זוֹ אֲבֵדָה. הֶחֱזִירָהּ וּבָרְחָה, הֶחֱזִירָהּ וּבָרְחָה, אֲפִילוּ אַרְבָּעָה וַחֲמִשָּׁה פְעָמִים, חַיָּב לְהַחֲזִירָהּ, שֶׁנֶּאֱמַר (דברים כב) הָשֵׁב תְּשִׁיבֵם. הָיָה בָטֵל מִ סֶּלַע, לֹא יֹאמַר לוֹ תֶּן לִי סֶלַע, אֶלָּא נוֹתֵן לוֹ שְׂכָרוֹ כְּפוֹעֵל בָּטֵל. אִם יֵשׁ שָׁם בֵּית דִּין, מַתְנֶה בִּפְנֵי בֵית דִּין. אִם אֵין שָׁם בֵּית דִּין, בִּפְנֵי מִי יַתְנֶה, שֶׁלּוֹ קוֹדֵם:
What is an aveidah ( a lost object)? [where it is evident that the owner is unaware if its whereabouts.] If he found an ass or a cow grazing on the road, this is not an aveidah [and he is not obliged to return it, it having been left there knowingly.] (If he found) an ass and its gear overturned, a cow running between the vineyards, [injuring its legs thereby], this is an aveidah. If he returned it and it ran away; returned it, and it ran away — even four or five times — he must keep on returning it, it being written (Deuteronomy 22:1): "Return shall you return them." [The Torah added many "returnings."] If he lost a sela (of working time in returning the aveidah), he may not tell him (the owner): "Give me a sela," [for the other can tell him: "Had you done your own work, you would have exerted yourself more. Take, then, the amount of your exertion."], but he gives him his wage as an idle worker, [i.e., the reduction in pay one would take to be idle from his regular, more difficult work, in order to do this work (of returning the aveidah)]. If there is a beth-din there, he makes a condition before beth-din. [If he does not wish to idle himself from his work, his wage being high, what does he do? If there are three men there (a beth-din), he makes a condition before them, viz.: "See, I am earning this and this amount. I do not wish to idle myself from my job and earn less. If you agree to my receiving my regular wage, I shall undertake to return this aveidah."] If there is no beth-din there, before whom shall he make a condition? His (claim) takes precedence [and he bypasses the aveidah].