Specific Rules #4 for Place of Publication (required) for Entire Books Vancouver Style: No place of publication can be found

If no place of publication can be found on the title page or its verso (back), but one can be found elsewhere in the publication or can be reasonably inferred (e.g., Chicago as the place for a publication of the American Medical Association), place the city in square brackets, such as "[Chicago]".

Marquis DK. Advance care planning: a practical guide for physicians. [Chicago]: AMA Press; c2001. 105 p.

If no place of publication can be found or inferred, use [place unknown].

Kuttner L. A child in pain: how to help, what to do. [place unknown]: Hartley & Marks; 1996. 271 p.

Según:

Citing Medicine: The NLM Style Guide for Authors, Editors, and Publishers [Internet]. 2nd edition. Chapter 2: Books

Related:

General Rules for Place of Publication (required) for Entire Books Vancouver Style

Specific Rules #1 for Place of Publication (required) for Entire Books Vancouver Style: Non-US cities

Specific Rules #2 for Place of Publication (required) for Entire Books Vancouver Style: Joint publication

Specific Rules #3 for Place of Publication (required) for Entire Books Vancouver Style: Multiple places of publication

Specific Rules #4 for Place of Publication (required) for Entire Books Vancouver Style: No place of publication can be found

Examples for Place of Publication (required) for Entire Books Vancouver Style (2015/08/25)