* and the Eb may be played with the right-hand D trill key. 
**In some recent performances, I have discovered some easier ways to perform some particularly difficult passages in the ensemble literature. Some may be aware of these possibilities, but since they are not shown in the alternate fingering and trill charts that I own, I thought some oboists might be interested in my findings.
In the Trio for piano, oboe, and bassoon of Francois Poulenc, the third movement is particularly challenging for the oboist. (see ex. 1). The Db may be played * and the Eb may be played with the right-hand D trill key. **
These two alternate fingerings make a somewhat difficult passage rather easy. It might be noted that while this fingering worked on my old Lorée oboe BU80, it did not work as well on my newer Lorée FB55. This same fingering passage is also effective for the final two measures of the work. (see ex. 2).
In the Trio en Ut for oboe, clarinet, and bassoon of Claude Arrieu, the third movement has this line in the oboe part. (see ex. 3) In the actual performance I used the standard fingering but I found an alternative for the D ** to Eb 
*** in my practice.
* sk = side octave key / bok = back octave key
**= D trill key right side
***= Db trill key left side
In the Victor Bruns Trio for oboe, clarinet, and bassoon Op. 49. movement three the oboe part is this. (see ex. 4). I play the C# , the regular fingering for the E on the left with the G# and Eb keys, and the Eb like this 
. Both the C# and the Eb are a little flat, but at this tempo (quarter note = 160) it is not so noticeable. The C# could also be played to help the pitch.
These alternate fingerings may not work for every person in every situation but perhaps some oboists may find them useful.