[For more current case annotated texts by this author, see Bernstein & Lookofsky, Understanding the CISG in Europe, 2d ed. (2003) and Lookofsky, Understanding the CISG in the USA, 2d ed. (2004).]
97. CISG Article 21(2), concerning late acceptance, and Article 29(2), concerning contract modification, both make use of the term 'writing'. Article 13 defines this term as follows:
98. According to Article 13, the term writing 'includes' telegram and telex. On the other hand, Article 13 does not define the term to exclude such increasingly popular means of communication as telefax transmissions or electronic data [page 60] exchange; these should also be treated as 'writings' under Article 13. This 'matter' - though not expressly settled in the Convention - is arguably 'governed' by it, and an expansive reading of the term writing to include more modern, yet clearly analogous; means of communication might arguably be said conform with the 'general principle' on which the Convention (at least Article 13) is based. It may be noted in this connection that Articles 21(2) and 29(2) do not require that a writing be signed.