Teachers' practice in class has been studied in many research works. But teachers' activity takes place not only in class, but also out-of-class. Moreover, during this work in class or out-of-class, teachers interact with various kinds of resources (Adler 2010): textbooks, students' productions, software, websites, videos. The available resources quickly evolve, with the development of digital material. Teachers look for resources, select resources, transform them, share them, set them up in class. In the perspective of the documentational approach of didactics (Gueudet & Trouche 2009), this has been called their documentation work. Along this work teachers develop documents, which associate resources and a scheme of use of theses resources (Vergnaud 1998) for a precise objective of the activity.

We study the documentation systems of teachers concerning three academic subjects : English, Mathematics, Physics, in the frame of a national research project in France called “ReVEA” (Lived resources for teaching and learning) supported by the French National Agency for Research (ANR).

We investigate teachers' documentation systems, which means that we do not only consider resources, but also interactions between teachers and resources, the links between teacher's knowledge and their documentation work. We study the following questions :

- do the documentation systems comprise « crucial resources », which means resources intervening in several documents, for different aims of the activity ? In this case, what are these resources, where do they come from, how are they related with the other resources used by the teacher ?

- which criteria intervene in the choice of resources by teachers : material criteria (for example the price of a textbook) ; criteria linked with precise didactical objectives (for example, which notations are used for vectors, on a mathematics website, or the authenticity of the English language used in a written text, or the time an experiment can take in physics or chemistry), criteria linked with the characteristics of the students etc. ?

- how and why do teachers modify resources, along their different uses of a same original resource, why do teachers stop using a resource, why do they share it with colleagues, what is the  « life cycle » (Hammoud, 2012) of a resource ?

- which factors lead to evolutions of the documentation systems, which means the evolution of teachers resources and the evolution of their professional knowledge ? We assume that the systems are relatively stable. They can naturally evolve when changes intervene in the official curriculum, but also if teachers encounter specific difficulties with some students, which create a need for new practices. We also suppose that collective work with colleagues makes the teachers' documentation evolve, particularly within groups of colleagues that have the features of a community of practice (Wenger, 1998 ; Gueudet, Pepin & Trouche 2013).

- what is the place of digital resources, in the teachers' resource system, and which evolutions of the documentation system result from the use of digital resources ?

We will try to establish common and different features in the systems of resources used by the teachers from different and same subjects, in order to question the reasons for these commonalities and differences, and to reveal some permanent features. In the end, the aim of the project is to make recommendations about how to take into account the issue of resources in teacher training, and to provide standards about educational resources for teachers.

Adler, J. (2000). Conceptualising resources as a theme for teacher education, Journal of Mathematics Teacher Education 3, 205-224. Hammoud, R. (2012). Le travail collectif des professeurs en chimie comme levier pour la mise en œuvre de démarches d'investigation et le développement des connaissances professionnelles. Contribution au développement de l'approche documentaire du didactique. PhD Thesis, Lyon I University, Lebanese University. Gueudet, G., Trouche L. (2008). Towards new documentation systems for mathematics teachers ? Educational Studies in Mathematics, 71(3), 199-218. Gueudet, G., Trouche, L., Sabra, H. & Hammoud, R. (2014). A documentational approach of didactics. (online), January, 7th 2015, http://educmath.ens-lyon.fr/Educmath/recherche/approche_documentaire. Trouche, L. (2014). Documentation valise. (online), December, 18th 2014, http://educmath.ens-lyon.fr/Educmath/recherche/approche_documentaire/documentation-valise/documentation-valise-1. Wenger, E. (1998). Communities of practice. Learning, meaning, identity. New York : Cambridge University Press. Gueudet, G., Pepin, B., & Trouche, L. (eds.) (2012). From Text to ‘Lived’ Resources: Mathematics Curriculum Materials and Teacher Development . New York : Springer.