epmc_refs() function retrieves only a subset of references for certain papers

[francivita]

I've been using the epmc_refs() function to fetch references for specific papers. For some paper IDs, it seems that the function only retrieves a subset of the references rather than the complete set. For in stance, this discrepancy has been observed for the paper with ID "36770874".

refs_subset <- epmc_refs("36770874", limit = 1000) #69 records found. Returning 69

Here the full text with 150 references https://europepmc.org/backend/ptpmcrender.fcgi?accid=PMC9921868&blobtype=pdf

[njahn82]

Hi @francivita the Europe PMC API just returns 69 records: https://www.ebi.ac.uk/europepmc/webservices/rest/MED/36770874/references?page=1&pageSize=25&format=xml

Seems like the API just returns refeferences with a PMID.

[njahn82]

Hi @francivita

Just a follow up. You can also make use of the DOI and query the Crossref API with the ropensci/rcrossref package.

Here is an example, which returns all 150 references. Hope it helps.

# Call Crossref API
library(rcrossref) 
cr_df <- rcrossref::cr_works("https://doi.org/10.3390/molecules28031208")

# Get tibble with reference data
cr_df$data$reference
#> [[1]]
#> # A tibble: 150 × 10
#>    key    unstructured     doi.asserted.by first.page DOI   article.title volume
#>    <chr>  <chr>            <chr>           <chr>      <chr> <chr>         <chr> 
#>  1 ref_1  FAO (2021, Nove… <NA>            <NA>       <NA>  <NA>          <NA>  
#>  2 ref_2  <NA>             crossref        1          10.1… Medicinal pl… 27    
#>  3 ref_3  Pushpgandhan, P… <NA>            <NA>       <NA>  <NA>          <NA>  
#>  4 ref_4  Prajapati, N.D.… <NA>            <NA>       <NA>  <NA>          <NA>  
#>  5 ref_5  <NA>             crossref        2373       10.3… Review Stero… 14    
#>  6 ref_6  <NA>             <NA>            397        <NA>  Post-infecti… 93    
#>  7 ref_7  <NA>             crossref        337        10.1… Distribution… 65    
#>  8 ref_8  <NA>             <NA>            1          <NA>  Therapeutic … 4     
#>  9 ref_9  <NA>             <NA>            2278       <NA>  Botanical, c… 1     
#> 10 ref_10 <NA>             <NA>            357        <NA>  Potential of… 13    
#> # ℹ 140 more rows
#> # ℹ 3 more variables: year <chr>, journal.title <chr>, author <chr>

^{Created on 2023-08-18 with reprex v2.0.2}