I have a series of TeX formulas where the author has put in spaces in the text, for example:

```
{\rm{Maximum credit}} = {{\mathop {{\rm{Net income from sources}}}\limits_{{\rm{without the United States}}} } \over {{\rm{Total net income}}}} \times \mathop {{\rm{United States tax on}}}\limits_{{\rm{total income}}}

```

Using [pdfTeX](http://tug.org/applications/pdftex/), this gets rendered without the spaces in the text:

[![Enter image description here](https://i.stack.imgur.com/TGQwy.png)](https://i.stack.imgur.com/TGQwy.png)

What do I need to do to the TeX formula to get the spaces to show?