Cite NumPy in BibTex

Looks right to me. That's how they ask to be cited, and it seems reasonable. Indeed, this discussion also agrees that citing the user manual is the right choice.

As to 2020, Numpy now has a Nature paper https://numpy.org/citing-numpy/

@Article{         harris2020array,
 title         = {Array programming with {NumPy}},
 author        = {Charles R. Harris and K. Jarrod Millman and St{'{e}}fan J.
                 van der Walt and Ralf Gommers and Pauli Virtanen and David
                 Cournapeau and Eric Wieser and Julian Taylor and Sebastian
                 Berg and Nathaniel J. Smith and Robert Kern and Matti Picus
                 and Stephan Hoyer and Marten H. van Kerkwijk and Matthew
                 Brett and Allan Haldane and Jaime Fern{'{a}}ndez del
                 R{'{\i}}o and Mark Wiebe and Pearu Peterson and Pierre
                 G{'{e}}rard-Marchant and Kevin Sheppard and Tyler Reddy and
                 Warren Weckesser and Hameer Abbasi and Christoph Gohlke and
                 Travis E. Oliphant},
 year          = {2020},
 month         = sep,
 journal       = {Nature},
 volume        = {585},
 number        = {7825},
 pages         = {357--362},
 doi           = {10.1038/s41586-020-2649-2},
 publisher     = {Springer Science and Business Media {LLC}},
 url           = {https://doi.org/10.1038/s41586-020-2649-2}
}

And if you use the new biblatex-software package, you can replace @Article by @Software

The proposed citation seems correct. I found the same at http://www.citebay.com/how-to-cite/numpy/.

@book{oliphant2006guide, 
  title={A guide to NumPy}, 
  author={Oliphant, Travis E}, 
  volume={1}, 
  year={2006}, 
  publisher={Trelgol Publishing USA} 
}