Add some people (external links)

I've added some people that just have external links for now.

README.md

@@ -29,13 +29,16 @@ they're ones I've read or have added to my to-read list.
 * [Bob Edwards](#bob-edwards)
 * [Anders Ericsson](#anders-ericsson)
 * [Paul Feltovich](#paul-feltovich)
+* [Pedro Ferreira](http://www.resilience-engineering-association.org/user/pedro/)
 * [Meir Finkel](#meir-finkel)
 * [Ivonne Andrade Herrera](#ivonne-andrade-herrera)
 * [Erik Hollnagel](#erik-hollnagel)
 * [Leila Johannesen](#leila-johannesen)
 * [Gary Klein](#gary-klein)
+* [Elizabeth Lay](https://www.linkedin.com/in/bethlay/)
 * [Nancy Leveson](#nancy-leveson)
 * [Carl Macrae](#carl-macrae)
+* [Laura Maguire](https://www.linkedin.com/in/lauramaguire/)
 * [Anne-Sophie Nyssen](anne-sophie-nyssen)
 * [Elinor Ostrom](#elinor-ostrom)
 * [Jean Pariès](#jean-paries)