Taanis2: 8
כָּל הַכָּתוּב בִּמְגִלַּת תַּעֲנִית ,,דְּלָא לְמִסְפַּד” — לְפָנָיו אָסוּר, לְאַחֲרָיו מֻתָּר;  רַבִּי יוֹסֵי אוֹמֵר: לְפָנָיו וּלְאַחֲרָיו אָסוּר.  ,,דְּלָא לְהִתְעַנָּאָה בְהוֹן” — לְפָנָיו וּלְאַחֲרָיו מֻתָּר;  רַבִּי יוֹסֵי אוֹמֵר: לְפָנָיו אָסוּר, לְאַחֲרָיו מֻתָּר.
Whenever it is written in the Scroll of Fasts, “Not to eulogize [on a particular day],” [on the day] before it [fasting] is forbidden; [on the day] after it [fasting] is permitted.  R' Yose says: [Both] before and after it [fasting] is forbidden.  [Concerning days about which it is written in the Scroll of Fasts,] “Not to fast on them,” [both] before and after them [fasting] is permitted.  R' Yose says: Before them [fasting] is forbidden; after them [fasting] is permitted.
Taanis2: 9
אֵין גּוֹזְרִין תַּעֲנִית עַל הַצִּבּוּר בַּתְּחִלָּה בַּחֲמִישִׁי, שֶׁלֹּא לְהַפְקִיעַ הַשְּׁעָרִים. אֶלָּא שָׁלֹשׁ תַּעֲנִיּוֹת הָרִאשׁוֹנוֹת — שֵׁנִי וַחֲמִישִׁי וְשֵׁנִי; וְשָׁלֹשׁ שְׁנִיּוֹת — חֲמִישִׁי שֵׁנִי וַחֲמִישִׁי.  רַבִּי יוֹסֵי אוֹמֵר: כְּשֵׁם שֶׁאֵין הָרִאשׁוֹנוֹת בַּחֲמִישִׁי, כָּךְ לֹא שְׁנִיּוֹת וְלֹא אַחֲרוֹנוֹת.
We may not decree upon the community a [series of] fast[s] commencing on Thursday, so as not to cause a rise in the market prices. Rather, the first three fasts are on Monday, Thursday, and Monday; the second three, on Thursday, Monday, and Thursday.  R' Yose says: Just as the first [three fasts] are not [to commence] on Thursday, so too, neither the second [three fasts] nor the final [seven fasts may commence on Thursday].