Here is the official agreement for convoking a referendum*, agreed to and released on December 17, 2012 by CiU and ERC. You can find the original Catalan version here.
Annex 1: Process for convoking the referendum on the political future of Catalonia
Over the last 30 years, a large part of Catalan society has fully committed itself to transforming the Spanish state so that Catalonia could fit in well without having to renounce its legitimate national aspirations, its determination for self government, and its continuity as a nation. But Catalonia's attempts to fit into the Spanish state, thanks to Spain's consistent and reiterated negative responses are, today, a dead end. It is for that reason that CiU and ERC believe that Catalonia must begin a new era based on the right to self determination in order to guarantee social progress, economic development, a strengthening of the democratic process, and the promotion of our native culture and language.
To this end, CiU and ERC hereby manifest their explicit commitment and their political will to hold a referendum so that the People of Catalonia may democratically and freely decide their collective future.
Catalonia finds herself faced with an opportunity that only comes around once in many generations: the opportunity to construct a new country; the opportunity of the Catalan People to be the protagonist of its own story; the opportunity to put politics in the center of public debate; the opportunity to create a better society based on social justice and equality; the opportunity to reaffirm our commitment with democracy, with peace, and with Europe.
Like any other nation, Catalonia must have tools of state that let it develop its own nation building project to the widest degree. Catalonia can live much better than it does now. It could if it had at its disposition, on the one hand, all of the resources that we citizens and businesses of Catalonia generate, and on the other, the power to make the necessary decisions, the political power over all of that which belongs to us and which affects us.
For these reasons, CiU and ERC express their commitment that the Catalan People be able to declare via referendum, whether Catalonia should become a State within Europe, and to have at its disposition, in this way, the tools necessary to get through the economic crisis, to favor growth, and to guarantee the cohesion and well-being of Catalan society.
To that end, and in function of the described commitments, CiU and ERC agree:
1. To formulate a "Declaration of Sovereignty of the People of Catalonia" in the First Session of the 10th legislature [the current one just constituted on 17 Dec], that will have as its goal to establish the commitment of the Parliament with respect to exercising the right of self determination of the People of Catalonia.
2. To approve the Law of Referendums starting from the work begun in the previous legislature, taking into account any changes and amendments that are agreed upon. To this end, a commitment is made to to promote the start of the parliamentary process by the end of January 2013, at the latest.
3. To open negotiations and a dialog with the Spanish State with respect to exercising our right to self determination that includes the option of holding a referendum, as foreseen in Law 4/2010 of the Parliament of Catalonia, on popular consultations, via referendum. To this end, a commitment is made to formalize a petition during the first semester of 2013.
4. To create the Catalan Council on National Transition, as an organ of promotion, coordination, participation, and advisement to the Government of the Generalitat with respect to the events that form part of the referendum process and the national transition and with the objective of guaranteeing that they are well prepared and that they come to pass.
This council will be comprised of people of recognized prestige and/or with representatives of the various areas linked to the process of national transition and the preparation and celebration of the referendum.
The Council must favor the participation in the process of those economic, social, and cultural entities of our country, as well as political formations that are in favor of the right to self-determination and the holding of a referendum.
5. CiU and ERC are committed to working through all of the formal, legal, and institutional procedures up until December 31, 2013 so as to be ready, from that date forward, to hold a referendum, in agreement with the legal framework that supports it, within the following year, unless the socioeconomic and political context requires that it be delayed, in which case, the date will be agreed on by the two signing parties.
6. Hold a referendum so that the People of Catalonia can declare their intentions on whether Catalonia should become a State within the European framework.
CiU and ERC agree to work to consolidate a wide social majority that ensures the success of the referendum and of the national transition process.
*referendum: There are two words for referendum in Catalan: consulta and referèndum. There isn't a good translation of consulta (a consultation in English might refer to a Doctor's appointment but not to a political referendum) and so I have translated both words as referendum here. Note however, that Spanish law does not allow Catalonia to have a referendum on self-determination and it's not yet sure whether it will be allowed to hold a consulta which is basically the same thing. Time will tell.