First let us check the references to the sources. There are references to J, as in 43:16-17,
כֹּה אָמַר יְהוָה, הַנּוֹתֵן בַּיָּם דָּרֶךְ, וּבְמַיִם עַזִּים, נְתִיבָה. הַמּוֹצִיא רֶכֶב-וָסוּס, חַיִל וְעִזּוּז; יַחְדָּו יִשְׁכְּבוּ בַּל-יָקוּמוּ, דָּעֲכוּ כַּפִּשְׁתָּה כָבוּ
and to E, as in 45:18-19,כִּי כֹה אָמַר-יְהוָה בּוֹרֵא הַשָּׁמַיִם הוּא הָאֱלֹהִים, יֹצֵר הָאָרֶץ וְעֹשָׂהּ הוּא כוֹנְנָהּ--לֹא-תֹהוּ בְרָאָהּ, לָשֶׁבֶת יְצָרָהּ; אֲנִי יְהוָה, וְאֵין עוֹד. לֹא בַסֵּתֶר דִּבַּרְתִּי, בִּמְקוֹם אֶרֶץ חֹשֶׁךְ--לֹא אָמַרְתִּי לְזֶרַע יַעֲקֹב, תֹּהוּ בַקְּשׁוּנִי; אֲנִי יְהוָה דֹּבֵר צֶדֶק, מַגִּיד מֵישָׁרִים
which refers to the first day of Creation, of E, not of P. (See the case of Yirmyahu, who also cites the first day of Creation.) We have seen that Deutero-Yeshaya refers to the Mabul, and in 61:1,רוּחַ אֲדֹנָי יְהוִה, עָלָי--יַעַן מָשַׁח יְהוָה אֹתִי לְבַשֵּׂר עֲנָוִים, שְׁלָחַנִי לַחֲבֹשׁ לְנִשְׁבְּרֵי-לֵב, לִקְרֹא לִשְׁבוּיִם דְּרוֹר, וְלַאֲסוּרִים פְּקַח-קוֹחַ
he refers to H (Vayikra 25:10). We conclude that E and J, including the Mabul, and the non-priestly part of H seem to be the works which the reader is assumed to know. These would be, in a sense, his Torah.However, Deutero-Yeshaya would probably not agree. He would have said that his writings are his Torah. To help one to learn this astounding and unique Torah, I wrote this post. It has verses which are like titles, each referring to a subject of his Torah.
As a first example, I wrote a post expounding on the verse:
נָּאווּ עַל-הֶהָרִים רַגְלֵי מְבַשֵּׂר, מַשְׁמִיעַ שָׁלוֹם מְבַשֵּׂר טוֹב--מַשְׁמִיעַ יְשׁוּעָה; אֹמֵר לְצִיּוֹן, מָלַךְ אֱלֹהָיִךְ
It shows the uniqueness, in my humble opinion. I will likely write more posts of this type, Im Yirtzeh Hashem.