Here are the references Ruth has suggested:
Transmedia Design Framework. Design-Oriented Approach to Transmedia Research,
https://www.researchgate.net/publication/289497151_Transmedia_Design_Framework_Design-Oriented_Approach_to_Transmedia_Research
This reading looks useful for -telling stories across platforms, consideration of how audience is involved in meaning making within this, defining terminology, reference list
Limitations of Transmedia Storytelling for Children: A Cognitive Developmental Analysis DANIEL PIETSCHMANN1 SABINE VĂ–LKEL PETER OHLER Chemnitz University of Technology http://ijoc.org/index.php/ijoc/article/viewFile/2612/1205DANIEL– useful for terminology, eg the differences between Transmedia Storytelling and Transmedia Franchises, case study on Cars
‘THE SCHNEIDERVERSE’ NICKELODEON, CONVERGENT TELEVISION AND TRANSMEDIA STORYTELLING, Helena Louise Dare-Edwards
Martin, C. (2009). Charlotte’s website: Media transformation and the intertextual web of children’s culture. Adaptation in contemporary culture: Textual infidelities, 85-95.
New directions in the rhizome of children's literature and children's culture: A case study in transmedia storytelling O'Daniel, KaTosha. The University of Tennessee at Chattanooga, ProQuest Dissertations Publishing, 2013. 1537097.
Kashtan, A. (2017). Multimodality Is Magic: My Little Pony and Transmedia Strategies in Children’s Comics. Graphic Novels for Children and Young Adults: A Collection of Critical Essays, 112.
Transmedia storytelling and entertainment: An annotated syllabus, H Jenkins - Continuum, 2010 - Taylor & Francis
Mann, Rachel. Southern youth: evoking Southern teenage identity through character design for animation: an exegesis presented in partial fulfilment of the requirements for the degree of Master of Design, College of Creative Arts, Massey University, Wellington, New Zealand. Diss. Massey University, 2015.