plagiarism in esl/efl learning contexts has been established as a dynamic and multi-layered phenomenon and has become a topic engaging many researchers in a heated debate in recent years. comparisons of student-generated texts with their source texts have shown that students rely on source texts in their writings and copying is a major strategy used by both l1 and l2 writers. in our country as an efl context also plagiarism has become a growing academic concern. aiming to contribute to this problem, this study first analyzes 7 postgraduate students’ academic writings at the english department of yazd university through a plagiarism detection software to identify their problems and the degree to which they rely on copying strategy in their l2 writings before and after the treatment. at the second stage, the effects of teaching two anti-plagiarism strategies of paraphrasing and citation on 19 postgraduate and 34 graduate students’ use of multiple sources in their writings are investigated. the treatment included a multidimensional course conducted in 30 minutes per week for 12 sessions and aimed at a) teaching correct quotation rules and the different functions of citation, while emphasizing the recognition of these rules at work and b) teaching lexical changes and grammatical changes in paraphrase writing. the writing samples of the students were 3 source-based writing tasks and 3 citation tests assigned before, during and after the treatment to convey improvements in students’ paraphrasing strategies and citation skills and the degree to which their writing strategies had approximated those of the l1 writers. keck’s (2006) new approach to the identification and classification of paraphrases within student writing (near copy, minimal revision, moderate revision, and substantial revision categories) was adapted to analyze students’ paraphrasing strategies in their summary writings. also, the effective citation strategies of students were analyzed according to their use of the standard citation style and for a high variety of rhetorical functions. the results of the assigned tasks and the two survey questions conveyed students’ perceived growing confidence and significant improvements in their citation skills and paraphrasing strategies in their source-based writings. the possible reasons for students’ insisting on copying at the end of the treatment are also discussed. the results can yield considerably insightful implications for writing course designers to treat significant problems of the students in their academic writings.