||Wang JH, Mechanobiology of tendon, J Biomech. 2006 39(9):1563-82 DOI: 10.1016/j.jbiomech.2005.05.011 p.1565 figure 1PubMed ID16000201
||Silver, F.H., Siperk, L.M., Seehra, G.P., 2003a. Mechanobiology of force transduction in dermal tissue. Skin Research and Technology 9, 3–23 AND/OR Silver FH, Freeman JW, Seehra GP. Collagen self-assembly and the development of tendon mechanical properties. J Biomech. 2003b Oct36(10):1529-53.PubMed ID12535279, 14499302
||P.1565 left column: "The tendon has a multi-unit hierarchical structure composed of collagen molecules, fibrils, fiber bundles, fascicles and tendon units that run parallel to the tendon’s long axis (Fig. 1). The fibril is the smallest tendon structural unit, it consists largely of rod-like collagen molecules aligned end-to-end in a quarter-staggered array. Fibril diameters vary from 10 to 500nm, depending on species, age, and sample location. Young animals have uniformly small fibrils, whereas mature animals typically have small and large fibrils, whose diameters are distributed in a bimodal fashion (Moore and De Beaux, 1987, Parry et al., 1982)." Please note-it isn't clear which of the primary sources was referred to in note beneath figure 1.