work upon

We will work upon the supposition that everything that is here belonged to Father.

The rest of the army then fell to work upon a great image of a horse.

He had his materials to work upon, and may have done the best that any one could with them.

There is not a blacksmith but is at his forge from morn to night at work upon pike-heads.

He is at work upon an 'Ars Poetica,' after the manner of Horace.

You cannot be very sick, then; you must not try to work upon our feelings.

He tried, too the effect of work upon the nervous depression from which he suffered.

Work upon the aviation camp at East Harniss had actually begun.

Unfortunately he based his work upon that of Schuch and Wuestemann and Lister.

Does it appear that the author had sufficient data to work upon?