Problem citing an article with author's last name with only 2 letters

Question

I want to cite the following article:

Snore Signal Enhancement and Activity Detection via Translation-Invariant Wavelet Transform

The authors list is:

Andrew Keong Ng and Tong San Koh and Kathiravelu Puvanendran and Udantha Ranjith Abeyratne

I am using Harvard style and what should happen when citing is:

(Ng et al 2008)

However, the citing result after compilation is:

(Ng, Koh, Puvanendran and Abeyratne 2008)

Adding an extra letter, for example Ngg, to the first author last name resolves the problem. The citing is:

(Ngg et al 2008)

This is not a solution and I am writing to ask if there a solution for this problem.

Here is an MWE

%\documentclass[12pt]{iopart}
\documentclass[12pt]{article}

\usepackage[main=english]{babel}

%\usepackage{iopams}
%\usepackage{setstack}
\usepackage{harvard}

\usepackage{filecontents}
\begin{filecontents}{\jobname.bib}
@InProceedings{Ng2008b,
    author    = {Andrew Keong Ng and Zhi Jie Ho and Tong San Koh},
    title     = {Effects of microphone position on snore signal quality and patient comfort},
    booktitle = {2008 9th International Conference on Signal Processing},
    year      = {2008},
    pages     = {2130-2133},
    month     = {oct},
    publisher = {{IEEE}},
    doi       = {10.1109/icosp.2008.4697567},
    keywords  = {acoustic signal detection; acoustic signal processing; distance 0.1 m; distance 0.3 m; distance 0.4 m; microphone position; mouth-to-microphone distance; obstructive sleep apnea detection; patient comfort; patient feedback survey; signal acquisition techniques; signal-to-noise ratio; sleep laboratory impulse response analysis; snore signal acquisition; snore signal analysis; snore signal quality; sound pressure level; Feedback; Humans; Laboratories; Microphones; Mouth; Position measurement; Signal analysis; Signal to noise ratio; Sleep apnea; Standardization},
}

@Article{Ng2008a,
    author    = {Andrew Keong Ng and Tong San Koh and Kathiravelu Puvanendran and Udantha Ranjith Abeyratne},
    title     = {Snore Signal Enhancement and Activity Detection via Translation-Invariant Wavelet Transform},
    journal   = {{IEEE} Transactions on Biomedical Engineering},
    year      = {2008},
    volume    = {55},
    number    = {10},
    pages     = {2332-2342},
    month     = {oct},
    doi       = {10.1109/tbme.2008.925682},
    keywords  = {Enhancement and detection; level-correlation-dependent (LCD) threshold; obstructive sleep apnea (OSA); snore activity (SA) detector; snore signals; snoring; translation-invariant discrete wavelet transform (TIDWT); wavelet thresholding},
    publisher = {Institute of Electrical and Electronics Engineers ({IEEE})},
}

@InCollection{Inoue2006,
    author    = {Kunihiko Inoue and Masatake Akutagawa and Takahiro Emoto and Udantha Abeyratne and Tetsuya Uemura and Hirofumi Nagashino and Yohsuke Kinouchi},
    title     = {Order Estimation and Screening of Apneic Snore Sound Using the Akaike Information Criterion},
    booktitle = {World Congress on Medical Physics and Biomedical Engineering 2006},
    publisher = {Springer Berlin Heidelberg},
    year      = {2006},
    pages     = {1135-1138},
    doi       = {10.1007/978-3-540-36841-0_272},
    keywords  = {Obstructive Sleep Apnea; auto-regressive model; Akaike Information Criterion; snore sound },
}

@InProceedings{Jane2000,
    author    = {R. Jané and J. Solà-Soler and J. A. Fiz and J. Morera},
    title     = {Automatic detection of snoring signals: validation with simple snorers and {OSAS} patients},
    booktitle = {Proceedings of the 22nd Annual International Conference of the {IEEE} Engineering in Medicine and Biology Society (Cat. No.00CH37143)},
    year      = {2000},
    pages     = {3129-3131},
    publisher = {{IEEE}},
    doi       = {10.1109/iembs.2000.901546},
    keywords  = {Detection; Neural Networks; OSAS Patients; Snoring; Validation},
}

@Article{Dafna2013,
    author    = {E. Dafna and A. Tarasiuk and Y. Zigel},
    title     = {Automatic Detection of Whole Night Snoring Events Using Non-Contact Microphone},
    journal   = {{PLOS} One},
    year      = {2013},
    volume    = {8},
    number    = {12},
    pages     = {1-14},
    month     = {Dec},
    doi       = {10.1371/journal.pone.0084139},
    owner     = {Tiago},
    timestamp = {2016.05.16},
}
\end{filecontents}


\begin{document}
  Although there is not a protocol for sound recording in sleep study, several studies used this position to record snores \cite{Ng2008b} \cite{Inoue2006}.
  The structure supporting the H4n was placed behind the bed with the distance between the H4n and the bed around 0.7m.
  \cite{Ng2008b} and \cite{Inoue2006} preferred a shorter distance, 0.3m and 0.5m, respectively but we increase the distance to decrease the probability of an accident with the patient.

  Automatic algorithms for snore detection had been proposed.
  \cite{Jane2000} used Neural Network for snore detection achieving a sensitivity of 82\% and a positive predictive value of 90\%.
  Wavelet-based algorithms also detect snores with an accuracy of up to 98\% \cite{Ng2008a}.
  \cite{Dafna2013} used an energy threshold method to do audio events detection.

  \section*{References}
  \bibliographystyle{jphysicsB}
  %\bibliographystyle{plain}
  \bibliography{\jobname}
  %\bibliography{MyPerBib}
\end{document}

Answer 1

It's not a bug, it's a feature!

The bibliography style jphysicsB.bst avoids abbreviating two different lists of names to the same short form (as in "X, Y, A" and "X, Y, B" do not both get shortened to "X et al.") since that might cause confusion. biblatex has a similar function, see Set limit to one author when using "et al." in biblatex, which can be turned off with the option uniquelist=false. Unfortunately, jphysicsB.bst does not have a simple option, so we will have to get our hands dirty and modify the style directly.

1. Locate jphysicsB.bst on your machine. You can do this by typing kpsewhich jphysicsB.bst into the command line/terminal. Alternatively, obtain a copy of the file from CTAN http://mirrors.ctan.org/macros/latex/contrib/harvard/jphysicsB.bst
2. Copy the file to a location where TeX can find it. The document directory will do fine.
3. Rename the file to jphysicsB-nouniquename.bst (this is a requirement of the license for jphysicsB.bst, a modified version of jphysicsB.bst must not bear the same name)

4. Open the file and find the following block of code

   EXECUTE {initialize.confusion}
   
   ITERATE {confusion.pass}
   
   EXECUTE {initialize.confusion}
   
   REVERSE {confusion.pass}
   

   in my version the lines can be found at ll. 1225-1231. Comment out the function calls so that the block now reads

   %EXECUTE {initialize.confusion}
   
   %ITERATE {confusion.pass}
   
   %EXECUTE {initialize.confusion}
   
   %REVERSE {confusion.pass}
   

5. Add your name and date and explain the modification in the comments at the top of the file.

6. Use \bibliographystyle{jphysicsB-nouniquename} instead of \bibliographystyle{jphysicsB} in your document.

With the new jphysicsB-nouniquename.bst

\documentclass[12pt]{article}
\usepackage[main=english]{babel}
\usepackage{harvard}

\usepackage{filecontents}
\begin{filecontents}{\jobname.bib}
@InProceedings{Ng2008b,
    author    = {Andrew Keong Ng and Zhi Jie Ho and Tong San Koh},
    title     = {Effects of microphone position on snore signal quality and patient comfort},
    booktitle = {2008 9th International Conference on Signal Processing},
    year      = {2008},
    pages     = {2130-2133},
    month     = {oct},
    publisher = {{IEEE}},
    doi       = {10.1109/icosp.2008.4697567},
}

@Article{Ng2008a,
    author    = {Andrew Keong Ng and Tong San Koh and Kathiravelu Puvanendran and Udantha Ranjith Abeyratne},
    title     = {Snore Signal Enhancement and Activity Detection via Translation-Invariant Wavelet Transform},
    journal   = {{IEEE} Transactions on Biomedical Engineering},
    year      = {2008},
    volume    = {55},
    number    = {10},
    pages     = {2332-2342},
    month     = {oct},
    doi       = {10.1109/tbme.2008.925682},
    publisher = {Institute of Electrical and Electronics Engineers ({IEEE})},
}

@InCollection{Inoue2006,
    author    = {Kunihiko Inoue and Masatake Akutagawa and Takahiro Emoto and Udantha Abeyratne and Tetsuya Uemura and Hirofumi Nagashino and Yohsuke Kinouchi},
    title     = {Order Estimation and Screening of Apneic Snore Sound Using the Akaike Information Criterion},
    booktitle = {World Congress on Medical Physics and Biomedical Engineering 2006},
    publisher = {Springer Berlin Heidelberg},
    year      = {2006},
    pages     = {1135-1138},
    doi       = {10.1007/978-3-540-36841-0_272},
}

@InProceedings{Jane2000,
    author    = {R. Jané and J. Solà-Soler and J. A. Fiz and J. Morera},
    title     = {Automatic detection of snoring signals: validation with simple snorers and {OSAS} patients},
    booktitle = {Proceedings of the 22nd Annual International Conference of the {IEEE} Engineering in Medicine and Biology Society (Cat. No.00CH37143)},
    year      = {2000},
    pages     = {3129-3131},
    publisher = {{IEEE}},
    doi       = {10.1109/iembs.2000.901546},
}

@Article{Dafna2013,
    author    = {E. Dafna and A. Tarasiuk and Y. Zigel},
    title     = {Automatic Detection of Whole Night Snoring Events Using Non-Contact Microphone},
    journal   = {{PLOS} One},
    year      = {2013},
    volume    = {8},
    number    = {12},
    pages     = {1-14},
    month     = {Dec},
    doi       = {10.1371/journal.pone.0084139},
}
\end{filecontents}


\begin{document}
  Although there is not a protocol for sound recording in sleep study, several studies used this position to record snores \cite{Ng2008b} \cite{Inoue2006}.
  The structure supporting the H4n was placed behind the bed with the distance between the H4n and the bed around 0.7m.
  \cite{Ng2008b} and \cite{Inoue2006} preferred a shorter distance, 0.3m and 0.5m, respectively but we increase the distance to decrease the probability of an accident with the patient.

  Automatic algorithms for snore detection had been proposed.
  \cite{Jane2000} used Neural Network for snore detection achieving a sensitivity of 82\% and a positive predictive value of 90\%.
  Wavelet-based algorithms also detect snores with an accuracy of up to 98\% \cite{Ng2008a}.
  \cite{Dafna2013} used an energy threshold method to do audio events detection.

  \bibliographystyle{jphysicsB-nouniquename}
  \bibliography{\jobname}
\end{document}

will yield