Macros for et al, e.g., i.e., etc.

Question

Possible Duplicate:
Macros for common abbreviations

Hi,

Taking et al. as an example, is it possible to make a one-shot macro like \etal that can actually handle all possible cases where you'd want to use this? All the scenarios I can think of right now are:

1. It falls in the middle of a sentence with no immediate other punctuation after it, in which case there should just be "et al." followed by the rest of the sentence without captilizing the next letter.

2. It ends a sentence, in which case there should be a single period which both abbreviates et al and ends the sentence.

3. It preceeds a comma, in which case I think it should still have a period to abbreviate et al, and the period should be followed immediately by a comma.

I think these scenarios are comparable for e.g., i.e., and etc. So, I have two questions:

1. Are my three scenarios correct or am I mis-using et al in any of them?

2. Can this be done with one simple macro, and if so, how?

I've included an example below where I've shown the behaviour of the macro included with my school's thesis template, which clearly doesn't handle all scenarios correctly.

Thanks.

\documentclass{article}[10pt.]


\newcommand{\etal}{{et al}.\@ }

\begin{document}

This reads correctly:

Smith \etal have contributed to the research. 

\vspace{1em}

These do not: 

\vspace{1em}

This was possible thanks to Smith \etal. Their work is great.

Should read: This was possible thanks to Smith et al. Their work is great.

\vspace{1em}

This work, introduced by Smith \etal, has many applications.

Should read: This work, introduced by Smith et al.\@, has many applications.

\end{document}