Wei, W., Yang, S., Zhou, H., Lieberwirth, I., Feng, X., & Müllen, K. (2013). 3D Graphene Foams Cross-linked with Pre-encapsulated Fe3O4 Nanospheres for Enhanced Lithium Storage. Advanced Materials, 25(21), 2909-2914. doi:10.1002/adma.201300445.