In this article we discuss dilemmas and paradoxes in the use of learning resources and the need to list sources when writing, issues that are relevant for students as well as for teachers and authors of textbooks. We draw on experience from a Norwegian research project investigating students' writing in two subjects: physics and Norwegian in senior high and university. We study the genres used when students write in order to get knowledge and skills, and we have a special interest in the use of learning resources. It is evident that the two subjects represent different text cultures, but we have seen that there are also similarities in the use of learning resources in writing. Methodologically, we have used interviews in focus groups in addition to personal letters from the students. In this article we are especially interested in students who are considered to be successful writers and even risk- writers, i.e. writers who are so self-confident that they have the courage to break with established norms and conventions. The risk-writers are aware of borders between intertextuality and plagiarism and know how to work with sources in order to be creative and innovative writers even though they do it in different ways in the two textual cultures. In conclusion we suggest possibilities for bridging the two cultures by changing the learning resources and textbooks and the way of writing.