Should Philip have P. or Ph. as an initial?

In the context of scientific articles and technical white papers, references to other publications typically include the author’s surname with, depending on the format of the specific publication, either their full first name or (most commonly) their initials.

In such cases, I sometimes see “Ph.” used instead of “P.” as initial for people named “Philip”. This does not seem linked to specific journal policies, but rather uncorrelated to the format of the references themselves. My questions are:

• How common is it? Is it considered standard practice?
• Are there other such examples in addition to “Ph.”?

Solution 1:

Aside from the English examples, initials with multiple letters are seen when transliterating from Russian. For example, "Yu. Gagarin" is "Yuri Gagarin" (Юрий Гагарин) since the "Yu" corresponds to a single Russian letter.

Solution 2:

The list so far includes:

• Charles - Chas. or Ch.

• George - Geo.

• James - Jas.

• Jonathan - Jon.

• Philip - Ph.

• William - Wm.

For a more comprehensive set, please see Wiktionary's list of abbreviations for English given names.