[1]
Gilbert Strang, The Fundamental Theorem of Linear Algebra, The American Mathematical Monthly November 1993, 100 no.β9, 848β855.
<appendix> to hold them, give it some structure (for an <article>, a leading <subsection>, such as the one you are reading right now), then follow with multiple <references> divisions. A typical citation will then look like: [J.3.2].