bibtex-prepare-new-entry is a compiled Lisp function in `
Prepare a new BibTeX entry with index INDEX.
INDEX is a list (KEY CROSSREF-KEY ENTRY-TYPE).
Move point where the entry KEY should be placed.
If `bibtex-maintain-sorted-entries' is non-nil, perform a binary
search to look for place for KEY. This requires that buffer is sorted,
Return t if preparation was successful or nil if entry KEY already exists.