A. ZZZ (2018).
\dQuote{A relation between several fundamental constants: \eqn{e^{i\pi}=-1}.}
\emph{A non-existent journal with the formula \eqn{L_2} in its name & an ampersand which is preceded by a backslash in the bib file.}.
This reference does not exist. It is a test/demo that simple formulas in BibTeX files are OK. A formula in field 'note': \eqn{c^2 = a^2 + b^2}.