Olszynko-Gryn, Jesse External, Max Planck Institute for the History of Science, Max Planck Society;
https://strathprints.strath.ac.uk/76813/1/Olszynko_Gryn_WH_2013_When_pregnancy_tests_were_toads_the_xenopus_test.pdf (Any fulltext)
Olszynko-Gryn, J. (2013). When pregnancy tests were toads: the Xenopus test in the early NHS. Wellcome History, 51, 2-3.