Who do you work for? <a href=" https://www.openmathtext.org/pregnancy-ultrasound-101-reasons-ultrasound-scans-essential/ ">para que sirve tabletas montelukast</a> The wheelchair-bound Hawking was diagnosed with motor neurone disease aged 21 and told he had two to three years to live. Now 71, he is one of the world's leading scientists, known especially for his work on black holes and as author of the international bestseller "A Brief History of Time".