Reference for Bava Batra 2:10

מַרְחִיקִין אֶת הַמִּשְׁרָה מִן הַיָּרָק, וְאֶת הַכְּרֵשִׁין מִן הַבְּצָלִים, וְאֶת הַחַרְדָּל מִן הַדְּבוֹרִים. רַבִּי יוֹסֵי מַתִּיר בַּחַרְדָּל:

A mishrah [a place where flax is soaked, which spoils greens that are near it] is distanced from greens, and leeks (are distanced) from onions, [leeks being harmful to onions which are near them], and mustard (is distanced) from bees, [mustard spoiling honey and making it sharp]. R. Yossi permits it with mustard, [for he can tell him: "Before you tell me to remove my mustard from your bees, remove your bees from my mustard! For they come and eat my mustard flowers!" The halachah is in accordance with R. Yossi.]

Jastrow