Grateful acknowledgement is made to the following sources:
Every effort has been made to contact copyright owners. If any have been inadvertently overlooked, the publishers will be pleased to make the necessary arrangements at the first opportunity.
224681: Figure 16 top left: © Dzmitry Kliapitski / 123 Royalty Free
224682: Figure 16 top middle: © Hannu Viitanen / 123 Royalty Free
224678: Figure 16 top right: © Sergey Rasulov / 123 Royalty Free
224683: Figure 16 bottom left: © Olga Zhavoronkova / 123 Royalty Free
224684: Figure 16 bottom middle: © Alex Postovski / 123 Royalty Free
224677: Figure 16 bottom right: © Lukas Gojda / 123 Royalty Free
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